LABORATORY MANUAL 

OF 

TESTING MATERIALS 



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LABORATORY MANUAL 



OF 



TESTING MATERIALS 



BY 

WILLIAM KENDRICK HATT, C.E., Pn.D. 

MEMBER AMERICAN SOCIETY CIVIL ENGINEERS; PROFESSOR OF CIVIL 

ENGINEERING, AND DIRECTOR OF LABORATORY FOR TESTING 

MATERIALS, PURDUE UNIVERSITY 

AND 

H. H. SCOFIELD, M.E. 

ASSISTANT PROFESSOR OF CIVIL ENGINEERING IN CHARGE OF TESTING 

MATERIALS, COLLEGE OF CIVIL ENGINEERING, CORNELL UNIVERSITY. 

MEMBER: AMERICAN SOCIETY FOR TESTING MATERIALS, 

SOCIETY OF AUTOMOTIVE ENGINEERS 



SFCOND EDITION 



McGRAW-HILL BOOK COMPANY, INC. 

NEW YORK: 239 WEST 39TH STREET 

LONDON: 6 & 8 BOUVERIE ST., E. C. 4 

1920 






COPYRIGHT, 1913, 1920, BY THE 
MCGRAW-HILL BOOK COMPANY, INC. 



THK M > >' 1. K PREHS YOKK PA 



PREFACE TO SECOND EDITION 

The methods of tests, specifications and related data 
have been revised and brought up to date. This has 
been particularly necessary in the field of concrete where 
developments have been rapid in recent years. 

It has been the intention to make the new edition use- 
ful in more than one institution by eliminating certain 
details of directions and apparatus which would be more 
or less peculiar to any one laboratory. It is felt that 
the generalized directions while being helpful as a guide 
in class work and investigations, should also lead to a 
more independent character of work upon the part of the 
student. 



435851. 



PREFACE TO FIRST EDITION 

This manual is the outcome of the operation, through 
eighteen years, of the Laboratory for Testing Materials 
of Purdue University. During this time several in- 
structors, temporarily serving the laboratory, have 
improved its practice. Especial mention should be 
made of the services of the late Professor Hancock, 
whose untimely death deprived the science of testing 
materials of a very able and patient investigator, and 
his colleagues of a good friend. Professor Yeoman, 
now of Valparaiso University, did valuable service in 
the organization of the work of the cement laboratory. 
The authors are indebted to Professor Poorman of 
Purdue University, for valuable suggestions. 

In its original form the manual was published by the 
senior author of this volume ; and later, with the assist- 
ance of Professor Scofield, the manual was enlarged, and 
was found useful in several universities. Now the 
authors have availed themselves of the assistance of the 
present publishers to enlarge the work. The list of ex- 
periments has been increased, and a more complete 
treatment of machines and apparatus added. 

One purpose of the manual is to relieve the instructor 
from the necessity of explaining the details of mechanical 
procedure, and so to free his time for matters of greater 
educational importance. It is also hoped by the authors 
that the practitioner will find the volume of convenient 
use. 

LAFAYETTE, IND., 
August, 1913. 



VI 



CONTENTS 



PAGE 

PREFACE ..... v 

CHAPTER I. GENERAL 1 

CHAPTER II. GENERAL INSTRUCTIONS 4 

Instructions for Writing Reports 7 

CHAPTER III. DEFINITIONS 10 

Stress 10 

Elasticity 12 

Resilience 14 

CHAPTER IV. MATERIALS STRESSED BEYOND THE ELASTIC 

LIMIT 16 

Fractures under Tension 17 

Fractures under Compression 17 

Fractures under Shear 19 

CHAPTER V. TESTING AISD TESTING MACHINES ..... 20 

Technical Qualities of Materials 20 

Testing Machines 21 

(a) Holding the Specimen 21 

(6) Method of Applying Lead 27 

(c) Weighing Mechanisms 35 

Extenso meters and Other Deformation Instruments . . 37 

CHAPTER VI. LIST OF EXPERIMENTS 44 

Experiments for Advanced Work 46 

CHAPTER VII. INSTRUCTIONS FOR PERFORMING EXPRRI 

MENTS . 48 

Article 1. Testing Machines 48 

A-l. Study of Testing Machines 48 

A-2. Calibration of Testing Machines 50 

A-3. Calibration of Extensometers 51 

vii 



Vlll 



PA.GK 

Article 2. Iron and Steel .............. 52 

B-l. Tension Test of Iron and Steel ....... 52 

B-2. Tension Test of Cast Iron or Steel Castings . . 55 

B-3. Autographic Tension Test of Iron or Steel . . 50 

B-4. Tension Test with Extensometer ...... 57 

B-5. Experiment in Torsion ........... 59 

B-6. Test of Wire Cable ............ 01 

B-7. Compression of Helical Spring ....... 02 

B-8. Effect of Overstrain on Yield Point of Steel . 03 

J3-9. Flexure Test of Cast Iron or Steel ...... 04 

B-10. Flexure Test of Brake Beam ........ 05 

B-ll. Vibration Test of Staybolt Iron ...... 05 

Articles. Test of Wood. ...... .......... 60 

C-l. Instructions for Laboratory Exercise for the 

Identification of Woods .......... 66 

C-2. Compression of Short Wood Blocks Parallel to 

Grain .................. 67 

C-3. Compression of Wood Perpendicular to Grain . 69 

C-4. Test of Wood Columns .......... 70 

C-5. Flexure Test of Small Wooden Beams .... 71 

C-6. Flexure Test of Large Wooden Beams .... 73 

C-7. Impact Test of Wooden Beams ....... 74 

C-8. Abrasion Test of Wood ...... .... 75 

Article 4. Tests of Cements ............. 70 

D-l. Test of Specific Gravity of Cement ...... 82 

D-2. Test of Fineness of Grinding ........ 83 

D-3. Normal Consistency ............ 85 

D-4. Time of Setting .............. 88 

D-5. Tests for Soundness ............ 87 

D-0. Cement and Cement Mortars in Tension ... 89 

D-7. Cement and Cement Mortars in Compression 92 

Articles. Study of Aggregates ............ 93 

Notes on Sampling of Aggregates ......... 93 

E-2. Test of Sand for Cleanness ......... 90 

E-3. Weight of Aggregates . . . ' ....... 99 

E-4. Specific Gravity of Various Materials Used as 

an Aggregate in Concrete ......... 102 

E-5. Determination of Voids in Aggregates .... 105 

E-6. Effect of Moisture in Aggregates on Per Cent. 

of Voids . . . 106 



CONTENTS ix 

PAGE 

E-7. Study of Sieves 107 

E-8. Sieve Analysis of Aggregates 109 

E-9. Hand Mixing of Concrete 113 

E-10. Mixing Concrete by Machine Mixer . . . .114 

E-ll. Amount of Water Required for Mixing . . .115 

Article 6. Proportioning Mortars and Concretes . . . .119 

E-12. Theory of Proportioning Concrete 119 

E-13. Mixture of Fine and Coarse Material . . . . 121 
E-14. Proportioning Concrete by Method of Sieve 

Analysis ... 122 

K-15. Strength in Relation to Density 127 

E-16. Surface Area of Aggregates 128 

E-17. Fineness Modulus of Aggregates 130 

Article 7. Tests of Concrete and Other Brittle Materials 132 
F-l. The Value of a Sand or Other Fine Aggregate 

as Shown by Strength Tests 132 

F-2. Compressive Strength of Concrete 133 

F-3. Compression Test Brittle Materials 134 

F-4. Compression of Brittle Materials with Defor- 
mation Measurement 136 

F-5. Reinforced Concrete Beam Test 137 

F-6. Bond Strength of Steel in Concrete . . . . .138 

F-7. Test of Concrete Reinforcing Fabric 139 

F-8. Cross Bending and Compression Tests of 

Building Brick 139 

Article 8. Tests of Road Materials 140 

G-l. Rattler Test of Paving Brick ........ 140 

G-2. Absorption Test 142 

G-3. Abrasion Test of Road Materials 142 

G-4. Cementation Test of Rock or Gravel or 

Materials of Like Nature 143 

G-5. Hardness Test of Rock Road Materials 

Dorry Test , 145 

G-6. Standard Toughness Test for Road Rock . . . 146 

APPENDIX I. COMMON FORMULAS 148 

APPENDIX II. Specifications for Materials 151 

Steel and Iron 151 

Methods for Metallographic Tests of Metals . ... 155 
Portland Cement .156 



x CONTENTS 

PAGE 

A.R.E.A. Aggregates 159 

Indiana State Highway Commission for Concrete 
Roads ICO 

APPENDIX III. STANDARD FORMS OF TEST PIECES ... 163 

APPENDIX IV. STRENGTH TABLES 165 

Iron and Steel 166 

Copper and Alloys 167 

StructuralTimber 168 

Stone and Brick 166 

INDEX ... . 171 



LABORATORY MANUAL OF 
TESTING MATERIALS 

CHAPTER I 
GENERAL 

1. The student should obtain a knowledge of materials 
by handling them and watching their behavior under 
stress. From the appearance before and after test, he 
is led to recognize the nature of normal and defective 
samples. This knowledge will give character to the 
work of engineering design, and will be of service in work 
of inspection. 

2. A knowledge of the technique of testing materials 
should be gained, by which he may know afterwards if 
proper methods are being used in cases that come under 
his inspection, and by which he may judge the signifi- 
cance of results of the tests of material submitted to 
him. 

3. A training should result in precise methods of 
observation. 

4. The class-room instruction in Applied Mechanics 
which should precede or accompany this course, is rein- 
forced with concrete knowledge of things and properties, 
which are otherwise only words denned in text-books. 
The application of theoretical analysis to the tests per- 
formed in the laboratory becomes of individual interest 
and is fixed in the mind. Discrepancies between theoret- 
ical deductions and results of tests of actual material as 

1 



MATERIALS 

supplied to the market also become evident. Many of 
the fundamental facts relating to metals, such as the 
relative stiffness of hard and soft steel, the elevation of 
the yield point, and the lowering of the elastic limit 
through overstrain can also be brought to the student's 
notice by a few well-selected experiments. 

5. The report which accompanies the investigational 
features of the work, affords practice in setting forth re- 
sults in a clear business-like way and should aid the 
student in forming at least the fundamentals of a style 
which will be later useful to him. 

6. The student should refer to standard text-books and 
specifications to compare the results obtained with 
recorded data. 

A partial list of specifications suitable for use is as 
follows : 

Specifications in Year Book of American Society for Testing 
Materials. 

Specifications in Year Book of State Highway Commissions. 
Materials of Construction by A. P. Mills. 
Materials of Construction by J. B. Johnson. 
Materials of Construction by Thurston. 
Materials of Construction by Upton. 
Mechanics of Materials by M. Merriman. 
Applied Mechanics by A. P. Poorman. 
Concrete Plain and Reinforced by Taylor and Thompson. 
Reinforced Concrete by G. A. Hool. 
Concrete Engineers' Handbook by Hool and Johnson. 
Mechanical Properties of Woods grown in the United States 
Bulletin No. 566 U. S. Dept. of Agriculture. 

7. Thesis work in testing materials presents a read} r 
and attractive medium by which students can receive 
some training in proper methods of planning and execut- 
ing experimental investigations. The work may be 
individual, or performed by groups of students, and 



GENERAL O 

the expense of material is small. If the professor is 
interested in some one field of investigation and system- 
atically plans for a term of years, the theses in time are 
of use in extending knowledge. 

The method of administering thesis work in general 
involves the following steps: A list of problems, to 
which, on account of limitations of equipment and the 
desire to concentrate, the work of the laboratory should 
be confined, is prepared early in the year. Theses sub- 
jects are generally chosen from this list by students. 
When a subject is chosen by a student, a thesis outline 
is prepared by the professor in consultation with the 
student, in which the problem is clearly stated; the 
authorities, if any, cited ; a list of literature, or directions 
to main source of information given; and the main 
plan of attack fairly definitely indicated. Details of 
apparatus, etc., are generally left to the student. A 
student may present a subject of his own choice. The 
written thesis covers a clear and logical account of the 
purpose of the thesis; the material tested; the methods 
and machines, with a discussion or error; the actual 
results; the analysis and presentation of the results; 
and the conclusions therefrom. 



CHAPTER II 
GENERAL INSTRUCTIONS 

Preliminary Notes. In all tests, first carefully ex- 
amine the material. Measure, and note characteristics 
and defects, if any. If this is not done before the speci- 
men is broken, the test is useless. Note the serial 
number if any. 

The character of the log sheet will be considered in 
grading the report. 

The student should understand the manipulation and 
reading of all instruments used in each test. 

Enough readings should be taken to accurately deter- 
mine the stress-strain curve. Calculate from table of 
average strengths of materials, see appendix, the incre- 
ment of loading required to give at least 18 readings. 
When quantities being measured are changing rapidly, 
intervals must be shortened. 

Specimens upon which further observations are to be 
made should be carefully marked and place in assigned 
case. 

If the reports are to be written in the laboratory during 
the assigned period, all notes and data, together with 
unfinished reports, must be left in the filing case. 

Operation of Machines During Test. Preliminary 
to every test, each student should become familiar with 
the operation and mechanism of the testing machine 
to be used. 

Balance poise at zero with test piece in the machine but 
free from the pulling head in every way. 



GENERAL INSTRUCTIONS 

All readings upon test piece for a certain load should 
be taken when the beam is balanced at the load and at 
no other time. The finger may be used to lift the beam 
slightly and so give warning which will prevent the 
loads being exceeded. 

The speed of applying the load should be such that 
the beam may be kept balanced, otherwise the readings 
will be of doubtful accuracy. 

Often after the elastic limit has been reached a faster 
speed may be used and much time saved. Any consist- 
ent speed is allowable if the load readings are accurate, 
except in experiments for which the machine speed to 
be used is stated in the instructions. Students should 
be sure that machines are properly thrown out of gear 
when the test is finished. 

CAUTION. Testing machines have upon different 
occasions been left by the operators with countershaft 
running and the friction clutches thrown in, so that the 
machines continued running. The result has usually 
been that some part of the machine was broken. The 
operator will take especial care that this does not occur 
with machines for which he is responsible. He will be 
charged with all the repairs made necessary by careless 
handling. 

Note Keeping.- The standard data sheets will in 
most cases be used for note keeping. In the case of 
most of the experiments the original log of the test will 
be required as a part of the report. Carbon copies of 
the original log made in the laboratory will be acceptable 
in case the work is of such a character that only one of 
two men can record the data obtained. Neat and 
orderly notes and test logs will be insisted upon. 

Reports. Reports will be written in ink or type- 
written on one side only of the standard 8" X 



LABORATORY MANUAL OF TESTING MATERIALS 



paper and placed in the regular manila cover. On the 
outside of the cover will appear the required information 
in lettering. 

Clearness and order of statement, legibility of writing, 
lettering and neatness will receive due attention in 
marking the report. 

In plotting stress-strain curves, select such a scale 
as can easily be read by inspection, in decimals. State 
plainly the scale of coordinates. Use the bow pen to 
circle the points plotted, and draw curves with instru- 
ments. Use India ink for curves and lettering on the 
curve sheets. Avoid lines from point to point. 



Max. 



Y.P. 




^ Deformation > > Deformation ^ 

FIG. 1. FIG. 2. 

FIGS. 1 AXD 2. Stress diagrams 

The general form of load-deformation curve should be 
noted. Figure (1) represents a characteristic curve of 
ductile materials where the curve is drawn a straight 
line to the elastic limit averaging the plotted points. 
Figure (2) represents the curve for brittle materials. 
Select scales of coordinates so that the slope of the 
portion below the elastic limit is about 60. As in Fig. 
1 when curve does not start at origin draw a parallel line 
through origin to the elastic limit. 

The title of the curve sheet should be placed in the 
lower right-hand corner and should contain such in- 
formation that a busy man unacquainted with the 



GENERAL INSTRUCTIONS I 

experiment, glancing at the curve sheet, would grasp 
the main facts without aid of the written report. 

The student will note carefully any characteristics of 
the curve that are peculiar and state reasons for their 
appearance and how they can be avoided if they seem to 
be errors. 

INSTRUCTIONS FOR WRITING REPORTS 

The clerical part of the report should be suitable for 
submission to a practising engineer, who would naturally 
judge of the qualifications of the writer by the neatness 
and system of the report. 

The sequence and the form in which the results are 
presented must be such as to enable a busy man to ascer- 
tain in a few moments just what was done and what 
was determined. A careful study should be given to 
economy of language in writing the report. 

SUGGESTED FORM OF REPORTS 

Title.- The title should indicate briefly what is 
covered by the report. 

Purpose. Under this heading the purpose, or pur- 
poses, of the tests should be concisely stated. - 

Materials Tested.- It is important that the materials 
tested should be concisely and definitely described. It 
is ordinarily sufficient to define the material as to its 
kind, size, shape and condition, although any other 
essential descriptive facts should be stated. Dimensioned 
sketches are frequently necessary to properly describe 
the test specimens. Reference should here be made to 
any sketches, descriptive of the material, appearing in 
an appendix or elsewhere in the report. Give page. 

Apparatus. Important special apparatus, only, 
should be listed and concisely and accurately described. 



8 LABORATORY MANUAL OF TESTING MATERIALS 

Diagrammatic sketches are frequently necessary to 
properly describe apparatus as used. Reference should 
be here made to diagrams or sketches descriptive of 
apparatus appearing elsewhere in, the report. 

Method of Test. Only the essential details of the 
testing procedure will be concisely and accurately given. 
It is not usually necessary to include in this division 
the unessential details of manipulation and measurement 
which are more or less common to all experimental 
work of this nature. It is important, however, to use 
good judgment in the selection and statement of such 
details of procedure, as to afford a proper and clear 
interpretation and comprehension of the results 
obtained. 

Results of Tests. The summarized results of the tests 
should be given under this heading. The results are 
usually most conveniently and clearly shown in sum- 
mary tables. Care should be taken that summaries 
should be accurate and concordant with the facts 
shown elsewhere in the report. Averages should be 
accompanied by a statement as to how many and what 
data are included. 

Discussion and Conclusions. Explain the significance 
of the curves used to present graphically the results of 
the tests. (It should be here emphasized that curve 
sheets should be clear and as far as possible self-explana- 
tory.) Where there are standard specifications for the 
material and test, a comparison with these standards 
should be shown. The standards should be quoted and 
authority and reference given. The specifications of 
the American Society for Testing Materials and other 
national societies should be consulted. 

Comparisons with published data by other authorities, 
along similar lines, are generally necessary for the proper 



GENERAL INSTRUCTIONS 9 

interpretation of the test results. Give references. 
Attention should be called to the factors affecting the 
accuracy, uniformity and validity of the results as shown. 

The significance and importance of the test and results 
should be discussed. 

The conclusions drawn should take all, of the above 
considerations into account, particularly those which are 
affected by the limitation of the testing apparatus used, 
the personal factor involved in ijie methods and special 
or unusual characteristics, or defects, in the test speci- 
mens visible either before or after the completion of the 
tests. 



CHAPTER III 
DEFINITIONS 

As supplementing the text-books in mechanics the fol- 
lowing definitions are recorded for reference : 

For formulas and symbols see Appendix. 

Stress is the internal, equal and opposite, action and 
reaction between two portions of a deformed body. 
Stress is a distributed force, and is expressed in force 
units. As in case of deformations, stresses are: (1) 
normal, S, either tensile (+) accompanying a lengthen- 
ing of a bar, or compressive ( ) accompanying a 
shortening of a bar; and (2) tangential or shearing, S v , 
when acting parallel to a section and accompanying 
achange of angle of the faces. 

Uniformly distributed normal stress accompanies a 
load that acts along a geometric axis of a bar. 

Unit stress (pounds per square inch) is the amount of 
stress per unit of area of surface. 

The word strain is often used to express both deforma- 
tion and stress. When used below it means deformation. 

Stress-strain diagrams (Fig. 3) are drawn from data 
obtained in tests of materials in which gradually increas- 
ing loads are applied from zero until rupture occurs. 
Unit deformations are shown as abscissae, and unit 
stresses as ordinates, tension (+) and compression 
( ). Such diagrams display the most important 
mechanical properties of materials. Figure 3 shows sev- 
eral such diagrams. The tension deformations at small 
loads are shown in magnified scale to the right and the 

10 



DEFINITIONS 



11 




FIG. 3. 



12 



LABORATORY MANUAL OF TESTING MATERIALS 



relative values of S p for various materials to the left. 
The stresses are not actual but nominal, because the 
load is divided by the original, and not by the actual, 
deformed area. 

ELASTICITY 

Elasticity is the tendency of deformed bodies to 
resume their former shape. 

Elastic Limit is the limit of stress within which the 
deformation completely disappears after the removal of 
the stress. As measured in tests, and used in design 
this term refers to the proportional elastic limit, S p , 
which is the unit stress within which stresses and defor- 
mations are directly proportional. At the Commercial 
Elastic Limit or Yield Point, S v , some materials experience 
a sudden and large increase of deformation without in- 
crease of stress. S p is from 0.75 S y (hot-rolled steel) to 
0.90 ^^(annealed steel). Location of S y depends upon 
speecffrf stress. 



KEY TO CURVES IN UPPER LEFT 



CORNER FIG. 3. 



Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
annealed 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 
Curve No. 



Curve No. 11 



A Soft O. H. Steel, as rolled. 

B Soft O. H. Steel, oil tempered and annealed. 

C Soft O. H. Steel, oil tempered. 

A Axle Steel, as rolled. 

C Axle Steel, oil tempered 

A O. H. Steel, forged disc. 

B O. H. Steel, forged disc, oil tempered and 

C O. H. Steel, forged disc, oil tempered. 

B Heavy Steel Casting, annealed 

A Cast Copper, annealed. 

B Cast Copper. 

C Hard Rolled Copper. 

Iron. 

;eel Casting, rim of small gear. 
Chrome Tungsten. 
Vanadium Steel. 




DEFINITIONS 



13 



Hooke's Law states that, within the elastic limit, the 
deformation produced is proportional to the stress. 

NOTE. Unless modified, the deduced formulas of me- 
chanics apply only within the elastic limit. Beyond this 
the formulas are modified by experimental coefficients, as 
for instance, modulus of rupture. 

Modulus of Elasticity (pounds per square inch) is the 
ratio of the increment of unit stress to increment of unit 
deformation within the elastic limit. 

The Modulus of Elasticity in Tension, or Young's 
Modulus, E, is graphically measured by the slope of 
OP (Fig. 3); the compression modulus by the slope of 
OP'. The inverse values of E for several materials 
express the relative unit deformations of these materials 
under the same unit stress. E is a measure of stiffness. 

Modulus of Elasticity in Shear, F, is the shearing 
unit stress divided by the angle of distortion exps^ed in 
radians. Theoretically, F = n/2E(n -f 1); and when 
n = 3, F = %E. (See Poisson's ratio.) 

Bulk Modulus of Elasticity, B, is the ratio of unit 
stress, applied to all side faces of a cube, to the unit 
change of volume. Theoretically, B = ^ En/(n 2); 
and when n = 3, B - E. 

Lateral Deformation, e' ', accompanies longitudinal de- 
formation, e. Poisson's Ratio, m, is the ratio of e' to e. 
The inverse value of m is denoted by n, that is, n = l/m. 

Values of m given by Unwin are: Flint Glass, 0.244; 
Brass, 0.333; Copper, 0.333; Cast Iron, 0.270; Wrought 
Iron, 0.278; Steel, 0.303; Concrete, according to Talbot, 
0.10. 

Change of volume, under long^J^nal deformation. 
/, d, b, = length, width and thicflHs; m = Poisson's 
ratio; s = unit deformation. Deformed volume 

- sms)b(l - ms)d=(l+s-2ms)lbd. 



14 LABORATORY MANUAL OF TESTING MATERIALS 

Fractional change of volume = (1 2m) s. When m is 
less than J^ the volume is increased in tension and 
decreased in compression. For steel, (m = }), change 
of volume is about J^ooo part at the elastic limit. 

A bar under stress does not at once assume the length 
due to its modulus of elasticity E. Deformation pro- 
ceeds for days and weeks. These phenomena of residual 
elasticity or elastic afterworking do not seem to be of prac- 
tical importance. 

RESILIENCE 

Resilience, K, (inch-pound) is the potential elastic 
energy stored up in a deformed body. For instance, a 
falling weight compresses a spring; the stored energy, or 
resilience, of the material is a source of work and will 
produce return motion in the weight. 

The amount of resilience i equal to the work required 
to deform the volume of material from zero stress to 
stress S. 

For longitudinal deformation ^Fig. 3), P load, 
e = deformation, S unit stress, E = modulus of 
elasticity, I = length, A = area cross section, V = 
volume. Resilience = work of deformation = average 
force X deformation = %Pe = ^AS Sl/E, or 

K = vy 2 &/E. 

The resilience for any other kind of stress such as shear- 
ing, bending, torsion, is the volume times a constant C 
times one-half the square of the stress divided by the 
appropriate modulus of elasticity. 

Resilience of solids of varying section cannot be ex- 
pressed per unit ojayolume. 

Modulus of rWMfence, K p (inch-pounds per cubic 
inch), or unit resilience, is the elastic energy stored up in 
a unit volume at the elastic limit. For longitudinal 



DEFINITIONS 



15 



deformation K p is graphically measured by the area 
OPP". (Fig. 3.) K p = H S*/E. 

RESILIENCE PER UNIT OF VOLUME K 

S = longitudinal stress, Sv = shearing stress, E = tension modulus of elasticity, 
F = shearing modulus of elastfcity 



1. Tension or compression 


y t s-/E 


SPRINGS. 




2 Shear 


}$Sv*/F 


Carriage 


1 ^<S 2 / E 


BEAMS, free ends 




Flat spiral rect. 


H*8*/B 


(Nos. 3-8) 




section. 




3. Rectangular section, bent in 








arc of circle. No shear 


}&S 2 /E 






4. Rectangular section, bent in 


}$S*/E 


Helical - axial 


XSv* 


arc of circle. Circular section. 




load, circular 








wire. 




5. Concentrated center load. Rec- 


HsS z /E 


Helical - axial 


y* SV*/F 


tangular cross section. 




twist. 




6. Concentrated center load. Cir- 








cular cross section 


Yi-zS-fE 






7. Uniform load. Rectangular 








cross section. 








8. I-beam section \ 


%zS z /E 






TORSION. (9-10) 








9 Solid circular 


\' Sv^/F 






10. Hollow, radii, Rt and Ri 


{ (Ri- + Rz 2 )/ 















The unit resilience stored up at a stress beyond the 
elastic limit is measured by the area of the triangle 
S"SS f (Fig. 3). 

Unit rupture work, K r , sometimes called Ultimate 
Resilience, is measured by the area of the stress-deforma- 
tion diagram to rupture, OPYMRR', (Fig. 3). 

K r = y$ e u (S y +2S m ) .... approx. (G) 

Here e u = the unit elongation at rupture. 

27 

For structural steel, for instance, K r = % nT (35,000 



+2 X 60,000) = 13,950 (inch-pounds per cubic inch). 



CHAPTER IV 



MATERIAL STRESSED BEYOND THE ELASTIC 

LIMIT 

Beyond elastic limit in tension S p , ductile materials 
like steel enter a semi-plastic stage. The material 
stretches from Y to L (Fig. 3) without increase of stress, 
and the scale beam of the testing machine "drops," 
and the hard mill-scale falls from bar. Yielding proceeds 
from either shoulder of bar to center. Steel shows both 
S p and S v ; cast iron, neither S y nor S p ; wood and 
hardened steel, S P) but no S y . 

The shape of the diagram from S p to S v depends upon 
speed of stress. Ewing found full line for fast, and dotted 
line, for very slow, speed (Fig. 3). 

After L semi-plastic and semi-elastic deformations pro- 
ceed. One or several contractions of cross section occur 
depending upon homogeneity of metal. The maximum 
load is reached at M (Fig. 3) when the metal at one of 
these contractions begins to flow. The contraction or 
"neck" proceeds until bar ruptures at R. The character 
of the metal changes under this excessive deformation, 
and, therefore, the actual stress on the ruptured section 
is not of practical importance, and is not observed. 

Ultimate strength S m = maximum load/original area. 
The elongation and contraction after rupture are 
observed. 

The load may be released at intervals to observe the 
set, OS" (Fig. 3). 

16 



MATERIAL STRESSED BEYOND THE ELASTIC LIMIT 17 

Fracture under tension indicates quality of mate- 
rial, but is influenced by speed and method of producing 
fracture, and by shape of test piece. A metal that is 
tough and fibrous may appear crystalline if broken 
quickly at a nicked section. Contraction is greatest 
in tough and ductile, and least in brittle, materials. 
The shape of fracture is usually a center flat surface of 
failure in tension surrounded by a rim on which the 
metal shears. The extent of the rim is more pronounced 
when the ratio of shearing to tensile strength is less; 
is more developed in soft steels; becomes a complete 
cone in very soft materials; and vanishes in cast iron. 
The color, grain and shear of the fracture are insignifi- 
cant. Forms of fracture in tension are shown in Fig. 4. 

Terms describing fracture are: silky, dull, granular, 
crystalline, fibrous. 

Failure under compression depends on material, 
slenderness of specimen, and restraint at ends or sides. 
Short blocks of brittle materials in compression like cast 
iron, stone, cement, when unconfined at the sides, fail by 
sliding along inclined planes. The angle of these planes 
is a function of the shearing stress and of the coefficient 
of friction of the material. The theoretical angle of frac- 
ture, with the cross section is ?r/4 -f- 0/2 where < is angle 
of repose of material. Internal cones, with their bases at 
the pressure heads of the testing machines, and pyramids, 
form in cylindrical and rectangular specimens 
respectively. 

Ductile or soft material, like copper and soft steel, 
cannot be ruptured in compression. They bulge, in- 
crease in diameter under increasing stress, and finally 
become plastic at the stress of fluidity. That is, the de- 
formation proceeds under a constant actual stress, per 
unit of deformed area, and is permanent. 



18 LABORATORY MANUAL OF TESTING MATERIALS 

The product of deformation and load (or normal stress) 
is then constant, and is expressed by a rectangular 
hyperbola. The outer portions of the stress strain 
diagram for lead and copper in Fig. 3 are approximately 
hyperbolic. 

Unwin quotes the following values for pressure of 
fluidity in pounds per square inch. Mild steel, 112,000; 
Copper 54,000; Lead 1700. Experiment by Hatt gives 
for wrought iron, 76,000. 

The strength of materials of medium ductility, like 
steel and wrought iron, in compression is generally to 
be taken at the yield point of the material. 



r\r\ 
^m 



U 




I / Copper Wrought Cast Stone Wood 

Iron Iron 

Steel 

FIG. 4. Characteristic fractures of materials in tension and compression. 



Strength under compression depends on ratio of 
length to diameter of specimen. 

The cornpressive strength of stone and concrete is 
about 10 times the tensile strength. 

Fracture forms for several materials in compression 
are shown in Fig. 4. 

Failure under pure shear is difficult to produce. The 
common form of test introduces bending stresses. 

Ratio of shearing strength to compressive strength is 
not well determined. For concrete and brittle materials 
this ratio is reported to vary from 0.32 to 1.25. 



MATERIAL STRESSED BEYOND THE ELASTIC LIMIT 19 

The ultimate shearing strength of steel and iron is 
nearly three quarters of its tensile strength. 

Hancock's Tests (Proc. Am. Soc. Test. Mat. 1908, 
p. 376) show that the shearing elastic limit of steel and 
iron, determined in torsion, is 0.50 to 0.57 the propor- 
tional elastic limit in tension. 

Failure of steel at or above the elastic limit is accom- 
panied by appearance of Hartmanris lines on polished 
surfaces. These lines make an angle, with the axis of 
a tension bar, of 63 for soft steel, and 58 for annealed 
steel. They indicate a slippage along the cleavage 
planes of the crystals of the metal. Steel consists of an 
aggregation of crystalline grains separated by films or 
membranes of material of different compositions. Un- 
der this view failure in tension or compression is 
essentially a failure under shearing stress modified by 
internal friction. 



CHAPTER V 
TESTING AND TESTING MACHINES 

Technical qualities of materials may be grouped as: 

Technological, having to do with manufacturing re- 
quirements, such as malleability, fusibility, forgeability, 
bending to shape. 

Physical, such as specific gravity, plasticity, homo- 
geneity, durability, structural characteristics, including 
fibrous, crystalline. 

Mechanical properties examined in tests. These are 
listed in table below, together with criteria commonly 
used. 



Quality 


Service Criteria 

1 


Example 


Strength 


To carry dead load. 


Ultimate strength. 


Piano wire. 


Elasticity. . . 


To undergo deformation i Amount of elastic 


Rubber. 




and return to shape. 


deformation. 




Resilience. . . 


To absorb energy with- Modulus of res- 


Second growth 




out permanent deforma- 


ilicnce. 


hickory. 




tion. 




Stiffness .... 


To carry load without de- 


Modulus of elas- 


Steel. 




formation. 


ticity. 




Hardness . . v 


To (a) withstand wear; 


Scratch tost; ab- 


Manganese steel. 




(6) to resist penetration. 


rasion test. 








Brinnel test. 




Toughness. . 


Various conceptions; to 


Various. 


Rivet steel; 




endure large permanent 




hickory wood 




deformations; to with- 








stand large energy with- 








out rupture. 






Endurance 


To withstand repetition 


Endurance test. 


Vanadium steel. 


iof stress with small 






shocks. 







Plasticity...! The absence of elasticity. 



Defornj without Lead, 
return or rupture. 



20 



TESTING AND TESTING MACHINES 21 

TESTING MACHINES 

Testing Machines must be accurate and sensitive. 

Accuracy depends on correct lever proportioning, 
condition of knife edges, and stiffness of levers. (See 
Experiment A-2.) 

For sensitiveness knife edges should be of small radius, 
and straight, and stiff. Knife edge machines are usually 
more sensitive than necessary. Machines should be 
examined for clearance of levers from frame of machine. 
(See Experiment A-2.) 

Specimens under test should not be subject to shocks 
or vibrations arising from the power elements of the 
machine, as for instance inertia of levers when specimen 
takes sudden elongation, or by the action of the pump in 
setting a body of liquid in motion. 

Machines vary in capacity from wire tester of 600 Ib. 
capacity to U. S. Govt. machines of 10,000,000 Ib. 
capacity in compression. For ordinary use in a com- 
mercial laboratory, a machine of 200,000 Ib. capacity is 
most suitable. For instruction of students a machine of 
30,000 Ib. capacity is most convenient. The present 
limit of screw-power scale beam machines for tension 
and compression is 1,000,000 Ib. 

The following table of large capacity testing machines 
is taken from an article by E. L. Lasier in the proceedings 
of the American Society of Testing Materials, 1913. 

Static testing machines must provide proper means for 
(a) holding specimen, (6) applying load, and (c) weighing 
the load. Mechanical problems of gearing, absorbing 
shock, and oiling must be solved. 

(a) HOLDING THE SPECIMEN 

Tension and Compression. It is important in testing 
a specimen in tension and compression, that the load 



22 



LABORATORY MANUAL OF TESTING MATERIALS 



OS O ffi O 'O 00 is. 

b- >-i O O OC O 

00 O O5 O Gi GS C^ 



fit 



<u o o> 

III 



es^sessssss&s sa 



CuCCCGflCCCMC 
csaJco3c8c8o3cSc8ci3a!a3 

13 13 "3 la Is 13 Is "c 13 S13 



. 

-S ^"3 

S 2 S 

U'U 

MWW WfflW W 



333 ^ ^ 

222 2 



jooooo; 



lllll 111 




:* : :S : 



88 rf ^ -CO 

^-11 ill 



ill ;IM22fiiiIl!* ;<s 






21: 



S 5-2 ci 

ssls-s^ 



^ n. . j" 

5 



TESTING AND TESTING MACHINES 



23 




FIG. 5. Universal joint for holding screw end test piece in tension, 



Head of Machine 

'A 



Bedding 



\S V >/ 



%?%!%%!%%%^^ 

Base of Machine 

Ifia. 6. Spherical bearing plate and method of supporting test piece in com- 
pression. 



24 



LABORATORY MANUAL OF TESTING MATERIALS 



is applied as nearly as possible in the axis of the test 
piece. This implies that the specimen should be ac- 
curately centered in the testing machine. The common 
method of holding the test bar is by serrated wedges 
with flat face, which is suitable for ductile materials. 
For brittle materials, or short specimens, it is customary 
to use a spherical, or universal, joint between the speci- 
men and the testing machine. These if correctly 
designed do away with bending and buckling in the 
specimen. 





Incorrect Correct 

FIG. 7.' Method of gripping test specimen in tension. 

Fig. 5 and 6 illustrate the adaptation of the universal 
joint to tension and compression tests. 1 Fig. 5 shows a 
convenient apparatus for gripping the standard short 
screw-end test piece and Fig. 6 shows the common 
method of supporting concrete or other like material in 
compression. A bedding of Plaster of Paris or blotting 
paper is used between the specimen and the surfaces of 
the machine, to give an even application of the load. 

Fig. 7 indicates a correct and an incorrect way to grip 
a specimen in tension. The test piece should extend 

1 NOTE : For compression tests of concrete the spherical bearing 
plate should be placed on top of the specimen. 



TESTING AND TESTING MACHINES 



25 



through the grips and these should have their full 
bearing over their entire length in the heads of the testing 
machine. 





FIG. 8. An apparatus for testing small beams in flexure. 




FIG. 9. A method of testing large beams in flexure. 



Flexure tests require freedom of specimen to bend 
and rollers should be placed between supports and 



26 



LABORATORY MANUAL OF TESTING MATERIALS 



specimen. In case an auxiliary straining beam in used, 
rollers are especially necessary to prevent compounding 
of straining beam and specimen through the horizontal 
shear at the loading points. 

Figs. 8 and 9 show apparatus as used by the Forest 
Service in the tests of timber, In Fig. 8, the supporting 
beam is conveniently laid across the weighing table of a 
small capacity testing machine. The rollers and plates 





FIG. 10. A shearing apparatus for wood. 

between supports and specimen prevent local failure 
and binding at the supports. 

In testing large beams, Fig. 9, it is customary to apply 
the loads at the third points by means of an auxiliary 
beam with rollers and plates. The knife edge supports 
are, in this case, so constructed that they rock freely as 
the beam bends downward. 

Shear Tests. Shearing shackles and tools should pro- 
duce pure shear without bending. Fig. 10 shows a 
simple and reliable shearing tool for tests of timber. 
It is supported directly on the weighing table of the 



TESTING AND TESTING MACHINEvS 



27 



testing machine and the plunger comes in direct contact 
with the under side of the movable head. 

; (b) METHOD OF APPLYING THE LOAD 

Loads are applied mainly by screw power (Olsen or 
Riehle); or (2) hydraulic power (Emery or Amsler). 




Fio. 11. Diagrammatic view of a Riehld testing machine. (Modified frojn 
Marten's Handbook of Testing Materials.) 

Screw Machines.- American machines are commonly 
of screw power. Old screw machines should be ex- 
amined to see if the wear of the threads produces an 
oscillatory motion of the testing heads. 

Fig. 11 represents by diagram a Riehle testing ma- 
chine. This is a two-screw machine. By rotation of 



28 



LABORATORY MANUAL OF TESTING MATERIALS 



the screws about their axes, the pulling head is moved up 
and down. Suitable gearing gives a variety of speeds in 
either direction. 

Fig. 12 shows an Olsen machine. This is generally 
a four-screw machine, sometimes three. In this type, 
the pulling head is made to move up or clown by the 
rotation of large geared nuts stationary in the base of 







FIG. 12. Diagrammatic view of an Olsen machine. (Modified from Marten's 
Handbook of Testing Materials.) 

the machine. Through these nuts pass the main screws 
to which is attached the pulling head. The screws do 
not turn on their axes. 

Hydraulic Machines Hydraulic machines, now 
becoming more popular, have many advantages in 
maintenance, steady loading, and in design of central 



TESTING AND TESTING MACHINES 



29 



power plant for laboratory! These sometimes involve 
friction of packing in cylinder, which is not important 
in large machines, and which is obviated in small ma- 
chines (Amsler) by use of a floating piston and a viscous 
fluid like castor oil. Proper provision should be made to 
hold a steady load. 

Fig. 13 shows the Amsler machine of small capacity. 




FIG. 13. Diagram of Amsler testing machine. (From Wawrziniok.) 

As shown, the machine is equipped with a hand pump 
and a mercury column load indicating device. To the 
right is shown the more common pendulum method of 
indicating load. 

Fig. 14 is a diagrammatic sketch of a vertical Emery 
testing machine. The hydraulic cylinder A is fixed to 



30 



LABORATORY MANUAL OF TESTING MATERIALS 



the frame D of the machine by the main rods SS. The 
plunger B is attached to the gripping apparatus. The 
weighing system is independent of the power system. 

Impact Machines.- Impact testing machines are (1) 
with vertical guides, or (2) of pendulum type. Pro- 
vision should be for meas- 
uring energy remaining in 
hammer after rupture of 
specimen. For this pur- 
pose, the hammer may fall 
on a spring (Fremont ma- 
chine), or, a pencil attached 
to the hammer may write a 
velocity d isplacement 
curve on a revolving drum 
(Turner machine). Method 
of release and hoist and 
mechanical details differ. 
Machines should be ex- 
amined for: (a) fit of ham- 
mer in guides; friction; 
proportion of height of 
hammer to clear width be- 
tween guides ; proportion of 
weight of hammer to foun- 
dation; perfection of release; shape of striking edge. 
Hammer should deform specimen as a whole. Loss of 
energy at surface of impact and in foundation due to 
inertia of specimen should be small. 

Fig. 15 illustrates the Turner vertical type of impact 
machine as used by the Forest Service in impact bending 
of small specimens. The pencil on the falling hammer 
makes a record on the revolving drum. 

The drum record, Fig. 16, represents a test of a spcci- 




FIG. 14. Diagram of a vertical Emery 
testing machine. (From Unwin.) 



TESTINU AND TESTING MACHINES 



31 



men broken in seven blows of increasing heights of 
hammer drop. The record gives the rebound heights 
and the deflection and set of the beam for each blow. 

The drum record, Fig. 17, represents a test of a speci- 
men broken in a single blow of the hammer. The drum 
velocity is given by the tuning fork record T-T. The 




FIG. 15. The Turner impact machine. 

datum line 0-0 is the position of the hammer at instant 
of striking the specimen. The velocity of the hammer 
at that point may be obtained from the slope of the 
curve at the point of crossing. Distance up from the 
datum line represents free fall of the hammer. Distance 
down from the datum line to point of rupture C repre- 
sents restrained fall of the hammer and deformation 



32 



LABORATORY MANUAL OF TESTING MATERIALS 



of the specimen. Below the point of rupture, the ham- 
mer has free fall and the residual energy may be com- 
puted from the velocity as given by the curve slope. 

Endurance Machines. The ability of metals to 
withstand a rapid reversion of stress is an important 
property. Heat-treated automobile or other machine 




Fro. 1C. Drum record, Turner impact machine. Specimen broken by seven 
blows of hammer. 

parts are tested for this quality by means of the endur- 
ance testing machine as shown in Fig. 18. 

The test piece A, accurately machined to size and 
shape, is rigidly gripped in the pulley B. The pulley 
is seated and free to turn in ball bearings in the frame F. 
By means of the yokes C-C and their weight supporting 



TESTING AND TESTING MACHINES 



33 




FIG. 17. Drum record, Turner impact machine. Specimen broken in single 

blow. 




FIG. 18. The White-Souther endurance testing machine. 



34 LABORATORY MANUAL OP TESTING MATERIALS 

standards, a load may be applied to each end of the 
test specimen. The pulley is made to rotate by belt 
connection to a motor. The speed of rotation is usually 
1300 r.p.m. The stress in the top and bottom is alter- 
nately tension and compression in rapid succession. 
Complete failure occurs at the edge of the fillets after a 
varying number of revolutions and at a stress below the 
elastic limit of the metal. 

Special Test. Hardness is not well defined, nor 
uniformly measured. Unwin defines it as resistance to 
permanent or plastic deformation. In this definition 
it is distinguished from resistance to abrasion which is a 
compound of other qualities. 

The best test for hardness is the Brinell Ball test. A 
hardened spherical ball (10 mm. diam.), is forced into a 
flat surface under a static pressure of 3000 kg. and 500 kg. 
for soft metals. The time of pressure should be at 
least 30 seconds. The specimen is 10 mm. thick and 35 
mm. wide. Hardness = pressure / curved area of de- 
pression. A fixed ratio exists between hardness and ten- 
acity of steels. Martens uses the depth of the impression. 
With balls 5 mm. in diameter the ratio of load to 
depth is constant within a depth range of 0.05 mm. The 
hardness number is the load necessary to indent material 
to 0.05 mm. 

For instance, Brinell hardness number is as follows. 
Acid Bessemer steel, carbon 0.10, hardness number: 
rolled, 100; annealed, 96. Basic Bessemer steel, carbon 
0.12, hardness number: rolled, 76; annealed, 81. 

A more recently perfected method for determinations 
of hardness is by means of the Scleroscope. In this 
instrument the height of rebound of a small diamond 
pointed tup is taken as a measure of the hardness of the 
surface upon which it is caused to fall. The height of 



TESTING AND TESTING MACHINES 



35 



drop is a fixed distance. The area of contact of the 
diamond point is so small that the metal upon which it 
strikes is stressed beyond the elastic limit. 

The tensile strength of steel in pounds per square 
inch is obtained from the following equations. 
TABLE 1. EQUATIONS CONNECTING MAXIMUM STRENGTH AND 

BRINELL NUMBERS 



Kind of steel 



Equations 



Carbon steel 


M 


= 


73 


B 


- 28 


Nickel steel 
Chrome-vanadium steel 


M 
M 


= 
= 


71 
71 


B 
B 


- 32 
- 29 


Low-chrome-nickel steel 
High-chrome-nickel steel 


M 
M 


= 
= 


08 
71 


B 
B 


- 22 
- 33 


All steels grouped together 


M 


= 


70 


B 


- 26 



TABLE 11. EQUATIONS CONNECTING MAXIMUM STRENGTH AND 
SCLEROSCOPE NUMBERS 



Kind of steel 



Equations 



Carbon steel 
Nickel steel 


M 
M 


= 4 

= 3 


4 

^ 


S - 
S - 


28 
fi 


Chrome-vanadium steel 
Low-chrome-nickel steel . 


M 
M 


= 4 
= 3 


2 

7 


S - 

,s - 


21 
1 


High-chrome-nickel steel 


M 


= 3 


7 


,sr - 


3 


All steels grouped together 


M 


= 4 





,s - 


15 















M is maximum strength in 1000 pound per square 
inch units. 

Reference. Proceedings of the American Society for 
Testing Materials, 1915. 

(c) WEIGHING MECHANISMS 

1. The most common type is the lever system. 
These are illustrated in Figs. 11 and 12, diagrammatic 
representations of the Olsen and Riehle testing machines. 



LABORATORY MANUAL OF TESTING MATERIALS 



All lever bearings and connections are hardened steel 
knife edges and plates. Load is indicated by the posi- 
tion of the poise p on the weighing beam. 

2. A gage or manometric column indicates the pres- 
sure in the cylinder of hydraulic machines. Sometimes a 
pendulum lever is employed to serve the same purpose. 

These types are illus- 
trated in Fig. 13 in the 
diagram of the Amsler 
machine. 

3. The pressure from 
the weighing table is 
transmitted to a hy- 
draulic pad H, in Fig. 
14, and thence to a mano- 
metric column or as in 
the Emery machine, to a 
separate lever system 
the fulchra of which are 
elastic plates. 

4. A less common type 
is that in which the de- 
formations of a portion 
of the frame of the ma- 
chine are measured. 

FIG. 19. The load is indicated by 

a measuring apparatus 

or by the change in volume of a hydraulic chamber 
which in turn is recorded on a fluid column. A diagram- 
matic view of this is shown in Fig. 19. The view shows 
one of the main rods B-B of the machine. This is 
fixed to the frame A of the machine. As the load comes 
on B, the deformation of B changes the volume of the 
chamber C-C, and is registered by a fluid column or 




TESTING AND TESTING MACHINES 



37 



other convenient means. The load value of the column 
is determined by calibration. 

EXTENSOMETERS AND OTHER DEFORMATION 
INSTRUMENTS 

For the determinations of yield point of tension bars 
and deflection of beams, instruments reading to 0.01 in. 
are sufficient. But for the determination of elastic 





FIG. 20. Yale-Richl6 extensometer. FIG. 21. Johnson roller cxtensomcler. 

limit and modulus of elasticity and for many other 
purposes, deformation instruments reading to 0.0001 in. 
are required* 

Extensometers may be classified: 

1. Micrometer screw, see Fig. 20. These are very 
reliable for experienced laboratory use but are seldom 



38 LABORATORY MANUAL OF TESTING MATERIALS 




v\ 



FIG. 22. Marten's mirror extensometer. 





FIG. 23. The Berry strain page. 



TESTING AND TESTING MACHINES 



39 



used for practical work. The contact of the micrometer 
points is best determined by means of an electric circuit 
and a telephone receiver in series. 

2. Roller dial (Johnson type), See Fig. 21. A simple 




Enlarged HoU for Berry St" 
Gage, in Steel Bar 

FIG. 23a. 




ert iu Concrete t'er Compression 

FIG. 235. 



A 




type for laboratory use but unreliable on account of 
slippage at the roller. There is also error introduced by 
the wear of the roller. The readings are given direct 
on the dials. 

3. Roller mirror, see Fig. 22. 
This is very delicate and reliable, 
but unsuited to student or routine 
work of the laboratory. The in- 
strument must be used where 
there is little vibration or jar. 

4. Lever type, examples of these 
are the Olsen Ewing and Berry. 
The last of these is particularly 
well adapted to a large variety of 
practical work both in the lab- 
oratory and in the field. In Fig. 
23 is shown this instrument as 
made with contact points for use 
in reinforced concrete work and 

with adjustable gage length. The contact points 
are placed in small counter-bored holes in the test 
piece. In some cases, the instrument may be fixed 
and held in testing position throughout the loading, 




FIG. 23c. Extensometer 
with Ames dials. 



40 LABORATORY MANUAL OP TESTING MATERIALS 

but generally it is removed after each reading is taken. 
In using the instrument, proper correction must be made 
for changes in temperature. The instrument reads 
directly to 0.0002 in. and closer by estimation of parts 
of a graduated division. 

The following precautions are taken in using the Berry 
strain gauge: 

1. The instrument is seated in the hole 5 times for an 
observed length. 

2. A preliminary series is taken in new holes. 




FIG. 24. Diagrammatic representation of an Olsen deflection instrument. 

3. After five sets of readings, the instrument is read 
on a standard bar to check up changes in the instrument. 

4. To reduce observations for temperature changes, 
readings are made on a specimen which is without load, 
and which is exposed in the same manner as the specimen 
under test. 

5. A single observer should make any set of readings 
and always in the same order. 

6. The instrument should be applied at right angles to 
the bar and with uniform pressure. 

Compressometers. The simplest type of compres- 
someter is shown by diagram in Fig. 24; this is a good 
practical instrument for rough work. It reads directly 
to 0.01 in. and by estimation to 0.001 in. 



TESTING AND TESTING MACHINES 



41 



Fig. 25 illustrates an instrument designed for closer 
more accurate determinations. This compressometer 
needs very careful handling for the best results. Better 
service may be accomplished by replacing the electric 
bell by a telephone receiver, to give the micrometer 
contact. The instrument reads directly to 0.0001 in. 




FIG. 25. The Olsen compressometer. 



A compressometer for short columns of timber which 
has been found very useful for student work by the 
authors, is shown in Fig. 26. Two yokes bearing Ames 
dials are attached to the specimen by four contact screws 
each. As the piece is deformed, the readings are given 
on both sides by the Ames dials. These read direct to 
0.001 in. and by estimation to 0.0001. 



42 LABORATORY MANUAL OF TESTING MATERIALS 




FIG. 26. Author's compression instrument for short wood columns. 




FIG. 27. Autographic apparatus. (From Wawrziniok.) 



TESTING AND TESTING MACHINES 43 

Autographic Recording Apparatus. A drum, Fig 
27, is fixed on the frame of the testing machine and put 
in gear with the specimen so that the rotation of the 
drum is proportional to the stretch of the specimen. A 
pencil in gear with the poise moves parallel to the axis 
of the drum. As the test proceeds, the diagram on the 
drum has abscissae of deformation and ordinates of load. 
In some types, the poise is replaced by a spring at the 
end of the scale beam. As the load is applied the scale 
beam rises and the spring measures the load. The rise 
of the beam actuates the pencil on the drum. This type 
yields delicate load measurements. A home-made 
simple autographic device is made of a steam-engine 
indicator on this plan. 

Autographic recorders are not suitable for the delicate 
measurements for elastic constants and are of limited 
use. 



CHAPTER VI 

LIST OF EXPERIMENTS 

PAGE 

ARTICLE 1. TESTING MACHINES , 48 

A-l. Study of Testing Machines. 
A-2. Calibration of Testing Machines. 
A-3. Calibration of Extensometers or other Measuring 
Device. 

ARTICLE 2. IRON AND STEEL. 52 

B-l. Commercial Tension Test of Wrought Iron and 

Steel. 

B-2. Commercial Tension of Cast Iron or Cast Steel. 
B-3. Autographic Tension Tests of Metals. 
B-4. Tension Test of Iron or Steel with Extensometers. 
B-5. Torsion Test of Iron or Steel. 
B-6. Tension Test of a Wire Cable. 
B-7. Compression Test of a Helical Spring. 
B-8. Effect of Overstrain on Strength and Elasticity 

of Steel and Iron. 

B-9. Flexure test of Cast Iron or Steel. 
B-10. Flexure Test of Brake Beam. 
B-ll. Vibratory Tests of Stay Bolts. 

ARTICLE 3. TESTS OF WOOD G6 

C-l. Study and Identification of Woods. 
-C-2. Compression of Wood Parallel to Grain. 
C-3. Compression of Wood Perpendicular to Grain. 
C-4. Compression of Wood Columns. 
C-5. Flexure of Small Wood Beams. 
C-6. Flexure of Large Wood Beams. 
C-7. Impact Tests of Wood. 
C-8. Abrasion Tests of Wood. 
C-9. Shearing Test of Wood. 
44 



LIST OF EXPERIMENTS 45 

PAGE 

ARTICLE 4. TESTS OF CEMENTS 76 

D-l. Tests of Specific Gravity of Cements. 

D-2. Fineness of Grinding. 

D-3. Normal Consistency. 

D-4. Time of Setting. 

D-5. Soundness. 

D-6. Strength of Cement and Cement Mortars in 

Tension. 
D-7. Strength of Cement and Cement Mortars in 

Compression. 

ARTICLE 5. STUDY OF AGGREGATES 93 

E-l. Sampling. 

E-2. Cleanness of Sand. 

E-3. Weight of Aggregates. 

E-4. Specific Gravity of Aggregate. 

E-5. Voids in Aggregate. 

E-6. Moisture in Sand. 

E-7. Study of Sieves. 

E-8. Sieve Analysis of Aggregates. 

E-9. Hand Mixing of Concrete. 

E-10. Mixing Concrete by Machine. 

E-ll. Water Required for Mixing. 

E-12. Theory of Proportioning. 

E-13. Proportioning Mortars and Concretes. 

E-14. Proportioning by Sieve Analysis. 

E-15. Strength in Relation to Density. 

E-l 6. Surface Area of Aggregates. 

E-l 7. Fineness Modulus. 

ARTICLE 7. TESTS OF CONCRETES AND OTHER BRITTLE 

MATERIALS 132 

F-l. Strength of Mortars Made up of a Given Sand. 

F-2. Compressive Strength of Concrete. 

F-3. Test of Brittle Materials Determining Strength 
at First Crack and Ultimate. 

F-4. Test of Brittle Materials Determining Strength 
and Elasticity. 

F-5. Flexure Test of Reinforced Concrete Beams. 



46 LABORATORY MANUAL OF TESTING MATERIALS 

PAGE 

F-6. Bond Strength of Steel in Concrete. 
F-7. Test of Reinforcing Fabric. 

F-8. Cross Bending and Compression Tests of Build- 
ing Brick. 

ARTICLE 8. TESTS OF ROAD MATERIALS ; 140 

G-l. Rattler Tests of Paving Bricks. 

G-2. Absorption Test of Paving Brick. 

G-3. Abrasion Test of Stone. 

G-4. Cementation Test of Stone or Gravel. 

G-5. Hardness of Stone as Determined in Dorry Test. 

G-6. Impact Test of Stone, Standard Test for Toughess. 

EXPERIMENTS FOR ADVANCED WORK 

The following list of experiments represents subjects 
for special tests to be carried out by the student. Some 
of these may also be made the subject of thesis 
investigation. 

Iron and Steel. Tension test of wire. Shearing 
tests of steel or iron. Tests of chains, hooks and rings. 
Tests of effect of shop methods on strength of steel 
and iron. Flexure test of I-beams. Tests of car 
bolsters, side frames, etc. Tests of flat springs in 
bending. Tests of built-up columns. Tests of metals 
in rapid reversion of stresses using White-Souther 
machine. Tests of various forms of joints. Tests of 
hardness of metals using Sclcroscope. Tests of alloy 
steels. Tests of steel plates. 

Wood. Tension of various wood splices and joints. 
Indentation tests of wood. Wood in shear. Torsion of 
wood. Spike pulling tests of wood. Plate and washer 
bearing in wood. Tests of wood paving blocks. Tests 
of treated timbers. 

Cement. Determination of weight per cubic foot of 
cement. Effect of fineness of grinding on properties of 



LIST OF EXPERIMENTS 47 

cement. Effect of varying amounts of gaging water. 
Effect of waterproofing methods upon strength and 
hardness. Tests for adulterants in cements. Effect 
of oils on properties of cements and cement mortars. 

Concrete. Strength of concrete with clay admixtures. 
Tests of concrete columns, plain and reinforced. Con- 
crete in shear. Bond of steel in concrete. Tests of 
concrete T-beams. Concrete arches. Tests of porosity 
and permeability of concrete. Electrolysis of steel in 
concrete. Machine vs. hand mixed concrete. 

Brittle Materials. Compression tests, fire tests, 
freezing tests. Absorption tests^ Test of patent 
roofing, flooring or other building material. 



CHAPTER VII 

INSTRUCTIONS FOR PERFORMING 
EXPERIMENTS 

Article 1 

TESTING MACHINES 

Experiment A-l 

STUDY OF TESTING MACHINES 

In this experiment, the student becomes acquainted 
with various types of testing machines and gains skill 
in their operation. 

References. Standard Methods for Testing, E 1-18, 
A. S. T. M. Standards 1918. Johnson's Materials of 
Construction-rewritten by Withey and Aston. Page 49. 

Materials. No material to be tested. 

Special Apparatus.- Various types of testing ma- 
chines as assigned. For each machine assigned, tabu- 
late: capacity of machine; name of builder; vertical or 
horizontal; number of screws; drive, i.e., belt, direct 
connected motor, hydraulic? 

Procedure. (a) Study operation of machine. Each 
student should become familiar with operation of ma- 
chines as he is responsible for breakage due to ignorance 
and carelessness. 

General Rules for Operators. 1. Do not start 
machine into a continued motion without first ascertain- 
ing the direction and speed with which it will move. 
Extra precaution in this respect must be used if the 

48 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 49 

movable head is near top or bottom of its range of 
movement. 

2. Do not start the machine with too sudden a motion 
as there is danger of stripping a gear, throwing a belt, 
or injury to electrical equipment. 

3. Do not reverse direction of motion or change 
speed without first stopping the machine. 

4. Stop and start the motion with the lever provided 
on the machine, not with the counter-shaft shifter, 
nor with the electric switch. 

5. When leaving the machine always see that the 
motion is stopped and counter-shaft is shifted to loose 
pulley. 

(b) Tabulate number and direction and value of 
the various speeds with which moving head can be 
moved. 

(c) Study and sketch the weighing table with lever 
system and weighing device. Measure and record all 
lever arm lengths. Sketch the various positions of 
control and speed levers. 

Discussion of Results. In the report, answer the 
following questions: 

1. Why is there need for centering the specimen in 
the testing machine? 

(a) With regard to effect on test piece. 
(6) With regard to effect on machine. 

2. Why can not the friction drive and main .clutch 
drive be used simultaneously? (This refers to Olsen 
friction type of machines only.) 

3. The slow speeds in the Olsen type of machine are 
sometimes obtained by a friction drive. In the Riehle 
type they arc obtained by a system of gearing. 

(a) Give advantages and disadvantages of the fric- 
tion drive for slow speeds. 



50 LABORATORY MANUAL OF TESTING MATERIALS 

(6) Give advantages and disadvantages of the geared 
drive for slow speeds. 

4. How is shock arising from rupture of specimen 
absorbed in the machine? 

5. Where are the main wearing surfaces in the machine ? 

6. What is the purpose of (a) the counter-poise, (6) 
the counter-weight? 

7. Upon what does the accuracy of a testing machine 
depend? 

8. Upon what does the sensitiveness of a testing 
machine depend? 

Experiment A-2 

CALIBRATION OF TESTING MACHINES 

References. Standard Methods for Testing, E 1-18. 
A. S. T. M. Standards, 1918. Johnson's Materials of 
Construction Rewritten by Withey and Aston, page 
50. 

Testing machines should be calibrated at least once a 
year. This experiment will show the common methods 
of- calibration. 

I. Accuracy of Machine Over a Part of Its Range 
of Load. The testing machine may be tested for accu- 
racy by loading the weighing table with standard weights. 
The weights should be placed uniformly on the table and 
beam readings taken for the various weights applied. 

This is the easiest and simplest manner of calibration of 
a testing machine but on account of the limited size of 
weighing table only a small part of the total capacity of 
the machine can be applied. However, the propor- 
tionality of the levers and weighing beam can be estab- 
lished and if the machine is correctly designed, the 
relation will hold constant for all loads. Auxiliary 
levers are also commonly used for this purpose. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS' 51 

II. Accuracy of a Machine Over a Part or All of Its 
Range of Load. If the accuracy of the machine over its 
whole range is desired, a known load may be applied by 
a standard calibration bar whose modulus of elasticity 
has been accurately determined. The bar should be of 
sufficient strength so that the load desired should not stress 
it to or near the elastic limit. The bar should be carefully 
centered in the machine and gripped with the spherical 
bearing nut at the end. The length of the bar measured 
by the extensometer shall be sufficient that the smallest 
division on extensometer shall correspond to a difference 
in loading of 0.2 per cent, of the capacity of the machine 
or less. The extensometer shall read deformations to 
0.0001 in. or less. 

The percentage of error in the testing machine may be 
determined by comparison of ihe determined modulus of 
elasticity (see Experiment B-4) with the previously 
known correct modulus of the standard bar. 

III. Tests of Sensitiveness of the Machine at Differ- 
ent Loads, Place in the machine a tension bar or a com- 
pression block of such size that the maximum load will 
not stress it to the elastic limit. Load the specimen to 
Mo> MJ an d ?lo the capacity of the machine. At 
each load, balance the weighing beam and place standard 
weights upon the weighing table. A weight ^50 of the 
load applied on the machine should produce a readable 
movement of the beam. 

Experiment A-3 

CALIBRATION OF EXTENSOMETERS OR OTHER MEASURING 

DEVICE 

Reference. Johnson's Materials of Construction 
Withey & Aston, page 100. Refer to Experiment B-4, 



52 LABORATORY MANUAL OF TESTING! MATERIALS 

Case I. Use a testing machine known to be accurate 
and a standard calibration bar whose modulus of elas- 
ticity is known. The extensometer to be calibrated is 
placed upon the bar in the usual manner and the modulus 
of elasticity determined in the usual way. The variation 
of the computed modulus from the correct modulus gives 
the error in the extensometer used. 

Case II. Using any bar and any machine determine 
the modulus with the extensometer to be calibrated and 
also with an extensometer which has previously been 
accurately calibrated. The variation in the modulus 
gives the error in the extensometer being calibrated. A 
convenient method is to use a bar of sufficient length to 
provide for both a standard extensometer and that to be 
tested. For greater refinement the extensometers may 
be interchanged in a second test. 

Case III. Direct comparison with any form of accu- 
rate measuring device may be made. Care must be 
taken to eliminate the effect of temperature changes, 
lost motion or other variables. 

Article 2 

IRON AND STEEL 

Experiment B-l 
TENSION TEST OF IRON AND STEEL 

The experiment is intended to represent the condi- 
tions obtaining in an ordinary commercial test with the 
exception that the speed of descent of the pulling head 
of the testing machine is much slower than customary 
in commercial laboratories. The experiment will deter- 
mine the strength and ductility of the material. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 53 

References. Materials of Construction Upton, Ar- 
ticles 48-75. 

Johnson's Materials of Construction Withey & Aston, 
page 104-110. 

Standard Methods for Testing, E 1-18; and Standard 
Specifications for Materials, of Amer. Soc. for Testing 
Materials, 1918. 

Material. Bars of iron or steel as furnished. 

Special Apparatus. Micrometer calipers, scale, di- 
viders. 

Procedure. 1. Give specimen a number and record 
this. 

2. With vernier or micrometer calipers determine the 
average dimensions of the cross section. Use average of 
three readings. 

3. Lay off gage length of 8 in., each inch being marked 
by a light center punch mark. 

4. Carefully balance the testing machine at zero of 
weighing beam after first loosening recoil nuts on weigh- 
ing table. Then insert the test-piece in the wedges, 
being careful that the test-piece is centrally disposed in 
the axis of the machine, and that the specimen is gripped 
to within 1 in. of the end gage marks. Tighten specimen 
in grips by applying a load of about 500 Ib. Chalk a 
small area of the bar near the upper gage mark. Before 
proceeding with the test allow the instructor to inspect the 
work. 

One student should insert one leg of a pair of dividers 
in the lower gage mark and scribe a line with the upper leg 
on the area previously chalked. Apply the load at a 
medium speed and operate the poise so as to keep the 
scale beam floating. 

The requirements of the Amer. Soc. for Testing Mate- 
rials as to speed are as follows: 



54 



LABORATORY MANUAL OF TESTING MATERIALS 



Specified minimum tensile 
strength of material, 
Ib. per sq. in. 


Gage length, in. 


Maximum crosshead speed, in. 
per minute, in determining 


Yield point 


Tensile strength 


80,000 or under < 
Over 80 000 { 


2 

8 
2 
8 


0.50 
2.00 
0.25 
0.50 


2.0 
6.0 
1.0 
2.0 





The operator with the dividers should continue to 
scribe the line and notify the operator at the poise when 
the width of the scribed line increases perceptibly due to 
sudden increase in the rate of stretching of the test bar 
under the load. At this time the beam may be expected 
to drop suddenly and remain down for an interval; also 
rough mill scale will fall from the specimen. This in- 
crease in elongation without a corresponding increase in 
load is the "yield point." It is a point beyond the true 
elastic limit as obtained in experiment B-4. 

During a further stretching of the bar the beam will 
again rise and should be kept floating up to the maximum 
load. At this maximum load the bar begins to neck in, 
the material becoming plastic at the point of the forma- 
tion of the neck. Leave poise at the maximum load, do 
not attempt to get actual breaking load. The stretching 
of the specimen should be continued until fracture occurs. 
Record in data sheet the load at yield point and the 
maximum load. 

Measurements after Tests. Lay the broken ends 
of the bar together and determine the increase in elonga- 
tion of the gage length. Measure the dimensions of the 
fractured area. Determine the rate of descent of the 
pulling head of the machine. Describe the appearance 



. INSTRUCTIONS FOR PERFORMING EXPERIMENTS 55 

of the fracture (see page 18) and determine the distance 
from the extreme gage point. 

Calculations. Calculate the ultimate tensile strength. 

Calculate the stress at yield point. 

Calculate the per cent, of elongation in gage length and 
per cent, of contraction of area at the fracture. 

In case the fracture is outside the middle third of the 
gage-length, the per cent, of elongation is to be measured 
and computed although a re test may be allowed in 
certain cases. This should be noted in the report. 

REPORT. See instructions for writing reports, page 7. 

Experiment B-2 

COMMERCIAL TENSION TESTS OF CAST IRON OR 
STEEL CASTINGS 

References. Specifications of Amer. Soc. for Testing 
Materials. Standards 1918. Serial A 27-16 and A48-18. 

The materials in this test are generally as follows: 

Cast Iron. Specimen in the rough, no machining; 
standard arbitration bar machined to standard size. 

Steel Casting. Standard machined test-piece using 
2-in. gage length. 

PROCEDURE. The method of test of cast iron is 
same as for Experiment B-l except that maximum load 
only is obtained. The method of test of steel castings is 
the same as for Experiment B-l except that a gage length 
of 2 in. is used. 

Computations. Make all computations as in regular 
test B-l, for steel casting specimens. For cast-iron speci- 
mens compute tensile strength. 

DISCUSSION OF RESULTS. Compare results with speci- 
fications and show in tabular form. 



56 LABORATORY MANUAL OP TESTING MATERIALS 

Experiment B-3 
AUTOGRAPHIC TENSION TESTS OF IRON OR STEEL 

This experiment may be performed by the instructor 
in front of the class to exhibit method used in commercial 
test B-l, and also by use of autographic diagram to show 
the general behavior of iron and steel when tested to 
rupture in tension. 

Materials to be Tested. The specimen should be a 
round bar of steel or iron. 

Apparatus. Besides the regular tension apparatus 
there should be the collars by which autographic appara- 
tus is attached to specimen. 

Procedure. All dimensions and descriptions of speci- 
mens should be noted as in the regular tension test. 
After attaching the collars to the ends of the gage length, 
the specimen should be placed in the machine and a 
small initial load applied to hold it. Arrange the auto- 
graphic apparatus so that the pencil is at the origin of 
diagram at zero load and zero stretch. Then apply the 
load continuously in a medium speed keeping the poise 
beam balanced. This may be done by the operator or 
by the mechanism in automatically balanced machines. 
Observe and record the load at yield point as given by 
the diagram, by drop, of the beam and scaling of the 
specimen. Observe the maximum load as given by 
the beam and diagram. 

Ascertain the elongation as given by the diagram and 
by actual measurement of specimen. 

Compute all results as obtained in regular commercial 
tension test. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 57 

Experiment B-4 

TENSION TEST WITH EXTENSOMETER 

In this experiment the strength and elastic properties 
of iron and steel in tension are determined. 

References. Standard Methods of Testing in 1918 
Standards of Amer. Soc. of Testing Materials. 

Materials of Construction Upton articles 39-48. 

Johnson's Materials of Construction Withey and 
Aston, page 111. 

Material. Wrought iron or steel. 

Special Apparatus. Extensometer reading to at least 
0.0002 inches. 

Note. The extensometers are delicate instruments 
and must be handled carefully. Any roughness of usage 
or lack of delicacy in manipulation will result in unsatis- 
factory diagrams. Be sure that the test bar is straight. 

PROCEDURE. Carefully measure and prepare each 
specimen as for regular tension test. See B-l. Tighten 
specimen in grips by applying an initial load equivalent 
to a stress of 2000 Ib. per sq. in. (the machine having 
been previously balanced). Apply and adjust the 
extensometer, noting the length between the contact 
points, and (after having had the apparatus inspected by 
the instructor) proceed with the test. Apply load in 
increments equivalent to a stress of 4000 Ib. per sq. in. 
for steel and 2000 Ib. per sq. in. for "iron and measure the 
total elongation at each load increment. When a stress 
of 30,000 and 20,000 Ib. per sq. in. for steel and iron 
respectively has been reached, apply loads in increments 
of one-half the former amount until, by the behavior of 
the beam, it is seen that the yield point is reached. 

After reaching a sudden and large increase in elonga- 
tion, remove the extensometer and apply load continu- 



58 LABORATORY MANUAL OF TESTIXO MATERIALS 

ously until specimen is ruptured, keeping beam balanced. 
Record maximum load. 

An actual stress instead of the commonly used nomi- 
nal tensile stress may, if desired, be obtained by taking 
readings of the new specimen diameters at each incre- 
ment of load. This may be continued through to the 
breaking point and readings of total stretch made by 
dividers. 

Construct a diagram with stress in pounds per square 
inch as ordinates and strain in inches per inch as abscissae. 
Draw a straight line averaging the points up to the 
more rapid increase in elongation (the elastic limit), 
and, tangent to the straight line draw a smooth curve 
averaging the remaining points. Ordinarily, the straight 
line of plotted points will not pass through the origin. 
Draw through the origin a line parallel to the straight 
line of plotted points. This line represents the true 
relation between stress and strain. Mark the elastic 
limit where the strain ceases to be proportional to stress. 

Calculations. Calculate stress at elastic limit, ulti- 
mate tensile strength, per cent, elongation and con- 
traction, modulus of elasticity, and modulus of elastic 
resilience. 

The modulus of elasticity is the stress in pounds per 
square inch divided by the elongation in inches per inch 
at any point on the straight line through the origin. It 
is most convenient to- select an abscissa of elongation of 
one part in 1000, and multiply the corresponding stress 
by 1000 to obtain the modulus of elasticity. 

The modulus of elastic resilience is the amount of work 
done on each cubic inch of the specimen in deforming it to 
the elastic limit. It may be taken as the equivalent in 
inch-pounds of the area under the straight line up to 
elastic limit; or it may be calculated by formula. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 59 

REPORT, The report should follow the standard form. 
It should be noted that this test is not a commercial test. 

Experiment B-5 

EXPERIMENT IN TORSION 

The object of this experiment is to study the behavior 
of materials under torsion, and to obtain such data as 
will enable the shearing strength of the material and its 
modulus of elasticity in shear to be computed. 

References. Materials of Construction Mills. 
Articles 490. 

Materials of Construction Upton. Articles 76-110. 

Johnson's Materials of Construction Wit hey and 
Aston. Articles 140-142. 

Bulletin No. 115, Engineering Experiment Station, 
Univ. of Illinois. 

Material. The material may be steel, iron, wood, or 
other material. 

Special Apparatus. Torsion Deformation instrument. 

Procedure.- Carefully measure the dimensions of the 
cross-section and lay off gage length. Then adjust the 
specimen in the heads of the machine, being careful that 
the specimen is fixed in the axis of rotation of the 
machine. Then apply the deformation instrument to 
the specimen and adjust the clamps of the latter so that 
the center of the circle of the graduated arc will be 
in the axis of the machine. Measure the distance from 
the axis of the specimen out to the graduated arc. 
Apply a small initial moment of about 100 in. Ib. and 
set to zero or record an initial reading of the graduated 
arc, and also the permanent scale on the twisting head 
of the machine. Measure the distance betweenVgrips. 

Experiment. Apply the loads by Increment of 200 
in. Ib. Read on the graduated arc the movement of the 



60 LABORATORY MANUAL OF TESTING MATERIALS 

pointer in inches for each increment. When tjie increase 
in the angle of torsion is found to be rapid, the elastic 
limit has been reached. The graduated arc and index 
should then be removed. 

If only the elastic properties of materials are to be 
determined the specimen may be removed. Ordinarily 
the tests are to be continued until the specimen is rup- 
tured. Read load every 180 turn. The whole angle of 
the twist is read from the fixed scale on the movable head 
of the machine. The scale beam should be kept bal- 
anced and the maximum load determined. 

Curves. Plot diagrams to suitable scales with the 
twisting moment in inch-pounds as ordinates and the 
unit deformation in radians per inch as abscissae. One 
of these curves will be drawn with the magnified abscissa 
and will show the points up to the elastic limit. The 
other curve will be on a small scale and will show the 
complete angle-moment diagram up to the rupture. As 
in other experiments, the straight line portion in the 
beginning should pass through the origin. If it does 
not, a straight line parallel to the straight line passing 
through the plotted points should be drawn through the 
origin and terminating at the elastic limit. Mark the 
points corresponding to the elastic limit and maximum 
load on the curve. 

Calculations. Compute (1) the shearing stress de- 
veloped at the elastic limit and the maximum load, 
using formula. (2) Calculate the modulus of elasticity 
in shear. (Use the coordinates of any point on the 
corrected curve of the magnified scale.) (3) Compute 
also the elastic resilience per cubic inch. 

Report. The report should follow standard form 
on p. 7. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 61 

Experiment B-6 

TEST OF WIRE CABLE 

The purpose of this test is to determine the strength 
of a wire cable by testing the separate wires. 

References Johnson's Materials of Construction, 
pages 69 and 94. 

Material. One piece of a wire cable about one foot 
long. Be sure it is a full strand. 

Procedure. Note strands in rope, number of turns 
per foot in strand, number of turns per foot in cable. 
Untwist wires of strand, note number of wire, determine 
the diameter in two places on each. Test each ^ire 
to rupture. Note breaking load. Calculate. 1. Ten- 
sile strength of wires in pounds per square inch. 2. 
Strength of cable. 3. Would cable be as strong as 
the sum of all the strengths of the individual wires? 
Why? 

Tests of wire rope as a whole may be made by properly 
brooming the ends, cleaning and tinning the wires and 
casting in babbitt metal in conical sockets so designed 
as to be gripped or held in the heads of the testing 
machine. 

The wires may be cleaned by dipping in gasolene 
followed by hot caustic potash. After cleaning, the 
wires should be dipped in zinc chloride and then tinned 
in molten babbitt. 

Report above items and submit in regular form. 

NOTE.- Tabulate the number of wires whose strengths 
are within 5 per cent., 10 per cent., 15 per cent., 20 
per cent, 25 per cent, of average strength, etc. 



62 LABORATORY MANUAL OF TESTING MATERIALS 

Experiment B-7 

COMPRESSION OF HELICAL SPRING 

References. Unwin's Strength of Materials. 

1918 Standards, Amer. Soc. for Testing Materials, 
serial A 61-16, page 124. 

OBJECT. A helical spring under load is a case of 
torsion. Springs are tested to determine their capacity 
and travel. The modulus of elasticity in shear and 
the resilience of the springs may be computed. 

Material. Two helical springs. 

Apparatus. Deflection instrument . 

Procedure. Measure height of spring, diameter of 
coil, diameter of wire and number of free turns. Place 
spring in testing machine as for compression. Deter- 
mine the following items as prescribed by the Amer. Soc. 
for Testing Materials: 

(a) Solid Height. The solid height is the perpendicu- 
lar distance between the plates or the testing machine 
when the spring is compressed solid with a test load at 
least \Y times that necessary to bring all the coils in 
contact. The solid height shall not vary more than % 
in. from that specified. 

(6) Free Height. The free height is the height of the 
spring when the load specified in Paragraph (a) has been 
released, and is determined by placing a straight edge 
across the top of the spring and measuring the perpendi- 
cular distance from the plate on which the spring stands 
to the straight edge, at the approximate center of the 
spring. The free height shall not vary more than } in. 
from that specified. 

(c) Loaded Height. The loaded height is the distance 
between the plates of the testing machine when the 
specified working load is applied. The loaded height 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 

shall not vary more than J^ in. over nor more than 
in. under that specified. 

(d) Permanent Set. The permanent set is the differ- 
ence, if any, between the free height and the height 
(measured at the same point and in a similar manner) 
after the spring has been compressed solid three times 
in rapid succession with the test load specified in Para- 
graph (a). The permanent set shall not exceed J^2 m - 
Apply 100 Ib. initial load; adjust the deflectometer. The 
load is applied by increments of pounds taking travel 
or compression at each load. 

Plot load-deformation curve, and energy-travel curve. 

Calculations. 1. Load at instant spring becomes 
solid (Maximum load). 2. Fiber stress in shearing 
at maximum. 3. Resilience per cubic inch at maximum. 
4. Modulus of elasticity in shear. 

Report should cover above elements and appear in 
general form. 

Experiment B-8 

EFFECT OF OVERSTRAIN ON YIELD POINT OF STEEL 

Reference. Burr's Elasticity and Resistance of 
Engineering Materials. 

Johnson's Materials of Construction Withey and 
Aston, page 661. 

Material. Steel bar about 18 in. long. 

Apparatus. Autographic extensometer. 

Procedure. Measure the dimension of the test 
piece and lay off a gage length of 8 in., marking each inch 
with a light prick punch mark. Fasten into machine, let 
automatic apparatus draw axis on sheet. Calculate 
probable elastic limit. Apply load to about two-thirds 
of this amount, keeping beam carefully balanced. Re- 
lease the load slowly, noting the path taken by the pencil 



64 LABORATORY MANUAL OP TESTING MATERIALS 

point. Apply load again until past yield point. Release 
as before. Repeat three or four times. Take all 
measurements as in B-3. For accurate work, a 
regular extensometer must be used. Note slope of 
curves. 

REPORT. Report should include analysis and discus- 
sion of results. 

Experiment B -9 
FLEXURE TEST OF CAST IRON OR STEEL 

This experiment is intended to show method of testing 
cast iron or steel in flexure and to give data for the com- 
putation of transverse strength. 

References. Standards 1918 of Amer. Soc. for Testing 
Materials, Serial A 48-18. 

Mills Materials of Construction, Art. 374 and 491. 

Johnson's Materials of Construction Withey and 
Aston, Art. 764. 

Material. A round, or rectangular bar of iron or steel 
of sufficient length to give a span of at least 10 in. 

The ''Arbitration Bar" of cast iron is a bar 1}^ in. in 
diameter and 15 in. long. The bars are in the rough and 
molded with special treatment. 

Special Apparatus. A deflectometer reading to 0.001 
in. 

Procedure. Arrange testing machine for transverse 
test with supporting knife edges at least 10 in. apart 
(12 in. for the " Arbitration Bar". See Appendix III). 
Compute breaking load (using table of strengths in 
appendix) and use an increment of load equal to Jf 5 of 
the breaking load. Measure deflection at center of 
span for each increment of load. 

Results and Conclusions. The report should be 
written in usual form and contain a comparison with 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 65 

specifications or other reliable data. Show load-de- 
flection curve. 

Experiment B-10 

FLEXURE TEST OF BRAKE BEAM 

Brake beams are required to pass certain specifications 
of the Master Car Builders' Association. 

Reference. Report of Master Car Builders' Associa- 
tion, Vol. 41, 1907. 

Material. Any brake beam complying with the M. 
C. B.- Standard Specifications for dimensions. 

"All beams must be capable of withstanding a load of 
7,500 Ib. at the center without more than ^{e i n - de- 
flection; where it is necessary to use a stronger beam, it 
must be capable of standing a load of 15,000 Ib. at the 
center without more than Jle m - deflection." 

Plot load-deformation curve. 

Results. Compare with M. C. B. specifications. 

See general form of report. 

Experiment B- 11 

VIBRATION TEST OF STAYBOLT IRON 

Staybolt iron should pass certain vibratory tests. 

Reference. Proceeding of American Society for Test- 
ing Materials, Volume 5, page 134. 

Material. Threaded staybolt iron of % in. to 1J 
in. in diameter. 

Apparatus. Olsen vibratory testing machine. 

Method. A threaded specimen, fixed at one end, has 
the other end moved in a circular path while stressed with 
a tensile load of 4000 Ib. The circle described shall have 
a radius of %2 m - at a point 8 in. from end of specimen." 
The speed of the machine shall be about 100 r.p.m. 



66 LABORATORY MANUAL OK TKSTINC MATH III A I ; S 

Results. Compare results with specifications of the 
American Society for Testing Materials. See H)ll Year 
Book. 

See general form of report. 

Article 3 

TESTS OF WOOD 

Experiment C-l 

INSTRUCTIONS FOR LABORATORY EXERCISE FOR THE 
IDENTIFICATION OF WOODS 

Purpose. The purpose of this experiment is practice 
in identification of timbers by appearance. 

References. Identification of the Economic Woods of 
the United States Samuel T. Record. 

Bulletin No. 10 of the Forest Service; and a pamphlet 
entitled " Trees of the United States Important in 
Forestry." 

Material. The material will consist of specimens ex- 
hibited in the Laboratory for Testing Materials, num- 
bered in consecutive numbers, including the common 
species of soft and hard woods; a key to these. 

Outline of Work. 1. Take the key to these woods and 
examine each in turn with reference to the material in 
the text mentioned above. Make notes concerning 
(a), in the hardness of the material, (6), the character of 
the grain as shown on the cross section, (c), the kind and 
distribution of pores, (d) t the relative proportion of 
spring and summer wood in the rings, (e) } color and 
appearance of the surface, together with whatever other 
external features will aid in the identification. Addi- 
tional short sections of the specimens on exhibit will be 
found hanging behind the large specimens. The large 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 67 

specimens should not be damaged, but the smaller 
duplicates may be cut with a jack knife to determine 
their working qualities. 

After this work is performed, the instructor will test the 
knowledge of the student by asking him to identify 
selected specimens of the woods. 

Report/ Report will describe six selected species, 
together with drawings of the structure of the wood as 
seen through the magnifying glass. The uses and sources 
of supply of the wood will also be described. 

Six SELECTED SPECIMENS 

I. White Oak. 
II. Red Oak. 

III. Yellow Pine (Longleaf). 
IV. White Pine. 
V. White Hickory. 
VI. Hard Maple. 

Experiment C-2 

COMPRESSION OF SHORT WOOD COLUMNS PARALLEL TO 

GRAIN 

References. Johnson's Materials of Construction 
Withey & Aston, page 196. 

Forest Service Circular No. 213. 

Timber, its Strength, Seasoning and Grading Betts, 
page 10, Table 3. 

This experiment may be preceded by the flexure of 
short beams C-5 and the material for this test taken from 
ends of short beams used in C-5. 

Materials to be Tested/ The columns to be tested 
are to be about 2 in. X 2 in. X 8 in. They should be sur- 
faced four sides with the ends squared and smooth cut. 



68 LABORATORY MANUAL OP TESTING MATERIALS 

The wood may be in the air dry, kiln dry, green, or 
resoaked condition as to moisture content. 

Apparatus. A compressometer reaching to at least 
0.0001 in. Collars, by means of which compressometer 
is attached to specimen. See Fig. 26. 

Deformations are more simply but less accurately 
measured by resting the measuring apparatus on the 
weighing table, and determining the travel of the move- 
able head of the testing machine. 

Procedure. Ascertain and record the following data: 
(a) Kind of wood, (b) Per cent, of heart and sap wood, 
(c) Per cent, of summer wood, (d) Annual rings per 
radial inch, (e) Dimensions of the test piece. (/) Note 
defects. 

Lay off the gage length, usually 6 in., on specimen and 
attach the collars at the ends of gage length. Place in 
the machine on the spherical bearing plate and center. 

Apply initial load equal to the first increment (gener- 
ally 1000 Ib. for the hard woods). After adjusting the 
compressometer to a zero reading apply the load by mere 
ments until the elastic limit has been reached. This is 
seen from the increased increments of deformation at that 
point. Take a reading for at least two loads beyond the 
elastic limit. 

Remove the compressometer and loosen the collars and 
then, applying the load continuously in the slow speed, 
obtain the maximum load. Carry the loading far enough 
to develop the character of fracture. 

Computations.- Plot a diagram for each specimen 
with load in pounds as ordinates and deformation in 
inches as abscissae. If the straight portion of the curve 
below the elastic limit does not pass through the origin, 
draw a parallel straight line through the origin. The 
load at elastic limit should be taken from this curve. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 69 

Compute. (a) Unit compress! ve strength at elastic 
limit. (6) Compressive strength at maximum load. 
(c) Modulus of elasticity, (d) Modulus of elastic 
resilience. 

The report should show sketches of fractured 
specimens. 

Experiment C-3 

COMPRESSION OF WOOD PERPENDICULAR TO GRAIN 

This experiment may be preceded by C-5 and the 
material for this test may be taken from ends of beams 
used in C-5. 

References. Johnson's Materials of Construction 
Aston & Withey, page 197. 

Forest Service Circular No. 213. 

Timber, its Strength, Seasoning and Grading Betts, 
page 10, Table 3. 

Materials/ Blocks about 2 in. X 2 in. X 8 in. finished 
four sides. 

The wood may be in the air dry, kiln dry, green or re- 
soaked condition as to moisture content. 

Apparatus. A compressometer reading to 0.0001 
in. A rectangular finished loading plate of cast iron or 
other metal 1 in. X2 in. X4 in. 

Procedure. Ascertain and record the following data: 
(a) Kind of wood. (6) Per cent, of heart and sap. 
(c) Per cent, of summer wood, (d) Annual rings per 
inch, (e) Dimensions of the block. 

Place the specimen in the machine flatwise and center. 
The loading plate should be placed on the specimen 
flatwise and long axis perpendicular to long axis of 
specimen. Apply an inital load equal to the first 
increment of load. 

Apply the load continuously, preferably by means of a 



70 LABORATORY MANUAL OF TESTING MATERIALS 

spherical bearing directly upon the loading plate, taking 
readings of compressions for increments of load as follows : 
800 Ib. for heart hard woods, and 400 Ib. for sap hard 
woods and 200 Ib. for soft woods. 

The loading should be carried to the elastic limit of the 
specimen. This may be seen from the increased incre- 
ments of deformation at that point. Do not try to 
obtain maximum load as there is none in specimens of 
this size across grain. 

Computations. Plot a diagram for each specimen 
with load in pounds as ordinates and deformations in 
inches as abscissae. The load at elastic limit should be 
taken from this curve. Compute unit compressive 
strength at elastic limit. 

Experiment C-4 

TESTS OF WOOD COLUMNS 

In this experiment, the behavior of the wood under 
column action may be learned together with constants 
of strength of columns. 

Reference. Church's Mechanics of Materials. 
Merriman's Strength of Materials. 

Material. Small wood columns of any species. 
They should be dressed on four sides, true to dimensions 
and have a slenderness ratio between 20 and 150. At 
least two columns of each species of wood of different 
slenderness ratios should be available for test. 

Procedure.- Ascertain and record all data as in Ex- 
periment C-2. 

Stretch a wire along the neutral axis of the narrow side 
of column. Any convenient method may be used to 
measure side bending or buckling of the columns. 
Great care must be taken in centering specimen in the 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 71 

machine. Apply small initial load and then determine 
zero reading of deflector at center of column. 

Apply load in increments of 1000 Ib. per square inch, 
taking readings of deformation for each instrument. 

The condition at ends may be one of the two cases: 
flat ends, hinged ends. Test in each condition of ends, 
two columns of different slenderness ratios. 

Calculations. Compute values of S and <j> for each 
species of wood and for each condition of ends. Use 
Rankines formula. 

Experiment C-5 

FLEXURE TEST OF SMALL WOOD BEAMS 

This experiment gives the strength and elasticity of 
woods as shown in tests of small specimens. 

Johnson's Materials of Construction Withey and 
Aston, page 196. 

Forest Service Circular No. 213. 

Timber, its Strength, Seasoning and Grading. Belts, 
page 10, Table 3. 

Materials. Two or more pieces of wood of oak, pine 
or other species. The size is about 2 in. X 2 in. X 28 
in. The specimens are finished on four sides. The 
wood may be in the air dry, kiln dry, green, or re-soaked 
condition as to moisture content. 

Apparatus. Deflection Instrument reading to 0.001 
in. 

Procedure. Ascertain and record the following data : 
(a) Kind of wood. (6) Per cent, heart wood and sap 
wood, (c) Per cent, summer wood, (d) Annual rings 
per radial inch, (e) Dimensions of piece. (/) Weight 
of specimen in grams, (g) Note defects such as knots, 
season checks, rot, etc. 

On one side of specimen mark the neutral axis and 



72 



LABORATORY MANUAL OF TESTING MATERIALS 



span-length and mid-span lines. The span to be used 
is ... in. 

Place the beam upon the knife edge supports, using 
short iron plates to prevent local crushing of the wood 
and binding between the supports. If there is clearance 
enough, two plates with two rollers between should be 
used at each support to allow freedom of bending. 
Apply an initial load of 100 Ib. and adjust deflection in- 
strument to read zero. See Fig. 8. 

NOTE. Common methods of measuring deflections 
are as follows: 

(a) Place a deflectometer on base of machine under- 
center of beam. (Fig. 24.) This is equivalent 
to having a scale or vernier attached to the loading 
yoke as in some special flexure machines. 
(6) Hang a special deflectometer on pins or tacks in 
the neutral axis over supports and attach the 
wire of needle to tack in neutral axis at mid-span. 
See that wire is vertical. (Fig. 8.) 
(c) Stretch a wire between tacks over supports and 
scale attached to beam at mid-span. A mirror 
or polished scale should be used so that image 
of wire may be seen, thus avoiding parallax. 
(Fig. 9.) 

Of these methods, the second is the most accurate but 
the first and last may be used in certain work. Apply 
the load continuously at a slow speed and take readings 
of deflection for increments of 100 Ib. load. If care is 
exercised, in keeping the beam balanced near the point 
of failure, it will be possible to read the correct load 
and deflection at failure even though this does not occur 
at one of the regular load increments. After obtaining 
the maximum load, carry the loading only far enough to 
develop the point and character of fracture. 



INSTRUCTIONS FOB PERFORMING EXPERIMENTS 73 

Sketch and describe fractures. 

Moisture Content of Specimen. Cut from the 
specimen near the point of failure a disk about 1 in. in 
thickness. Trim off all loose wood and weigh on sensi- 
tive balances. This moisture disk is to be oven-dried 
and again weighed. The loss in weight expressed as a 
per cent, of dry weight gives the per cent, of moisture 
in beam. 

For Tests in Compression. Saw from the beam al- 
ready tested, two test pieces 8 in. in length to be used in 
Experiments C-2 and C-3. 

Computations. Plot a diagram with load in pounds 
as ordinates and deformation in inches as abscissae. 
Draw the correction curve through the origin, if necessary. 
The load at elastic limit is taken from this curve. 

Compute.- (a) Fiber stress at elastic limit. (6) Mod- 
ulus of Rupture. (Fiber stress at maximum load.) 

(c) Modulus of Elasticity. (Use corrected deflections.) 

(d) Elastic Resilience per cubic inch, (e) Rupture 
work per cubic inch (/) Per cent, moisture, (g) Specific 
gravity. 

Discussion of Results. See general form of report. 

Experiment C-6 

FLEXURE TEST OF LARGE WOOD BEAMS 

The strength and elasticity of timber in full size speci- 
mens are determined in this test. 

References. Circular No. 38, of Forest Service. 

Johnson's Materials of Construction Aston and 
Withey, Articles 230-232. Bulletin of Forest Service 
No. 108. 

Material. Full size specimens of any wood in which 
span length does not exceed 16 ft. The specimens 



74 LABORATORY MANUAL OF TKSTIMi MATKKIAI^ 

may be finished or in the rough but should be sawed true 
to size and squared. 

Procedure. Ascertain and record all data as in Ex- 
periment C-5. The method of testing is the same as in 
C-5 except that the load is applied at the third points, 
to approach as nearly as possible to conditions of uni- 
form loading. Moisture content is obtained as in C-5. 

Computations. Make all computations as in Experi- 
ment C-5. 

Discussion of Results. Compare results with aver- 
age of other . tests upon same and different kinds of 
timber. 

Experiment C-7 

IMPACT TEST OF WOODEN BEAMS 

In determining the relative brittleness of different tim- 
bers, tests in impact bending will be made. 

Reference. Circular No. 38, Forest Service. 

Material/ Two 2 in. X 2 in. X 30 in. sticks. Any timber. 

Special Apparatus/ Impact machine. 

Procedure The resistance of a specimen of wood 
under impa t is usually determined by dropping a given 
weight from successively increasing heights. The suc- 
cessive amounts of deformation and set of the specimen 
and rebound of the hammer are recorded on the drum. 
The elastic strength of the specimen is fixed at that limit 
at which the deflection suddenly increases. At this limit 
a sudden increase in the set of the specimen, as well as a 
maximum amount of rebound of the hammer, usualh r 
occurs. 

In making the test the hammer is allowed to rest upon 
the upper surface of the specimen, and a zero or datum 
line is drawn on the drum. The deflection under the 
dead load of the hammer is obtained from a static cross- 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 75 

bending test of similar material. A corrected zero line 
can thus be drawn. Then blows of a weight dropped 
from increasing heights are delivered to the specimen, 
and records taken on the drum. A sample record is seen 
in Fig. 16. 

The height of the drop at which any rupture of the 
specimen occurs is noted, together with other phenomena 
of test. Sample log sheets and calculations will be found 
in the Appendix of Circular 38, Forest Service. 

The machine is calibrated in advance to determine the 
proportion of the height of fall which is not effective 
because of friction and lag of magnet. 

Occasionally the beam is ruptured under a single blow 
of the hammer falling from a height greater than that 
necessary to rupture the specimen. In this case the resi- 
dual energy resident in the hammer, after rupture of the 
specimen, must be determined in order that the amount of 
energy used up in rupturing the specimen may be known. 

The zero or datum line is determined as before, the 
hammer is released from a height greater than that neces- 
sary to rupture the specimen, and a record is* taken 
of the circumstances of the impact. The tuning fork 
must be held on the drum during impact. A sample 
record is shown in Fig. 17. 

Calculations. Determine rupture-work, height of drop 
at elastic limit and maximum. Specific gravity, etc. 

Experiment C-8 
ABRASION TEST OF WOOD 

Purpose. The purpose of this test is to determine^ the 
relative wearing ability of different woods. 

Material. 2 in.X2 in.X2 in. cubes of wood, three 
specimens, and three standard maple blocks. 



76 LABORATORY MANUAL OF TKSTING MATERIALS 

Apparatus. Dorry abrasion machine for wood. 

Methods. Measure blocks carefully at the four 
corners. Place blocks in machine in one of the six pos- 
sible ways (see instructor). The standard maple block 
and test specimens must be exactly the same and wear 
against the same portion of the paper. Run the machine 
at 68 r.p.m. until the standard or test specimen wears 
down about Y in., or, in time units, 15 minutes. 

Results. Measure again at four corners. Calculate 
volume worn away and per cent, of wear of test specimen 
in relation to that of standard specimen. 

Compare with other tests. 

Caution. Take care that weight of the holder is 
always on both pieces. 

Article 4 
TESTS OF CEMENTS 1 

VI. SAMPLING 
Number of Samples 

16. Tests may be made on individual or composite 
samples as may be ordered. Each test sample should 
weigh at least 8 Ib. 

17. (a) Individual Sample. If sampled in cars one test 
sample shall be taken from each 50bbl. or fraction thereof. 
If sampled in bins one sample shall be taken from each 
100 bbl. 

(6) Composite Sample. If sampled in cars one sample 
shall be taken from one sack in each 40 sacks (or 1 bbl. in 
each 10 bbl.) and combined to form one test sample. If 
sampled in bins or warehouses one test sample shall 
represent not more than 200 bbl. 

1 Authorized Reprint from the Copyrighted A. S. T. M. Standards 
(1018), American Society for Testing Materials, Philadelphia, Pa. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 77 

Method of Sampling 

18. Cement may be sampled at the mill by any of the 
following methods that may be practicable, as ordered: 

(a) From the Conveyor Delivering to the Bin. At least 
8 Ib. of cement shall be taken from approximately each 
100 bbl. passing over the conveyor. 

(6) From Filled Bins by Means of Proper Sampling 
Tubes. Tubes inserted vertically may be used for 
sampling cement to a maximum depth of 10 ft. Tubes 
inserted horizontally may be used where the construc- 
tion of the bin permits. Samples shall be taken from 
points well distributed over the face of the bin. 

(c) From Filled Bins at Points of Discharge.- Sufficient 
cement shall be drawn from the discharge openings to 
obtain samples representative of the cement contained 
in the bin, as determined by the appearance at the dis- 
charge openings of indicators placed on the surface of the 
cement directly above these openings before drawing 
of the cement is started. 

Treatment of Sample 

19. Samples preferably shall be shipped and stored in 
air-tight containers. Samples shall be passed through 
a sieve having 20 meshes per linear inch in order to thor- 
oughly mix the sample, break up lumps and remove 
foreign materials. 

VII. CHEMICAL ANALYSIS 
Loss on Ignition 

20. One gram of cement shall be heated in a weighed 
covered platinum crucible, of 20 to 25c.c. capacity, as 
follows, using either method (a) or (b) as ordered: 

(a) The crucible shall be placed in a hole in an as- 



78 LABORATORY MANUAL OF TESTING MATERIALS 

bestos board, clamped horizontally so that about three- 
fifths of the crucible projects below, and blasted at a 
full red heat for 15 minutes with an inclined flame; the 
loss in weight shall be checked by a second blasting 
for 5 minutes. Care shall be taken to wipe off particles 
of asbestos that may adhere to the crucible when with- 
drawn from the hole in the board. Greater neatness 
and shortening of the time of heating are secured by 
making a hole to fit the crucible in a circular disk of sheet 
platinum and placing this disk over a somewhat larger 
hole in an asbestos board. 

(6) The crucible shall be placed in a muffle at any 
temperature between 900 and 1000 C. for 15 minutes 
and the loss in weight shall be checked by a second 
heating for 5 minutes. 

21. A permissible variation of 0.25 will be allowed, and 
all results in excess of the specified limit but within this 
permissible variation shall be reported as 4 per cent. 

Insoluble Residue 

22. To a 1-g. sample of cement shall be added 10 c.c. of 
water and 5 c.c. of concentrated hydrochloric acid; the 
liquid shall be warmed until effervescence ceases. 
The solution shall be diluted to 50 c.c. and digested on a 
steam bath or hot plate until it is evident that decompo- 
sition of the cement is complete. The residue shall 
be filtered, washed with cold water, and the filter paper 
and contents digested in about 33 c.c. of a 5 per cent, 
solution of sodium carbonate, the liquid being held at a 
temperature just short of boiling for 15 minutes. The 
remaining residue shall be filtered, washed with cold 
water, then with a few drops of hot hydrochloric acid, 
1:9, and finally with hot water, and then ignited at u red 
heat and weighed as the insoluble residue. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 79 

23. A permissible variation of 0.15 will be allowed, and 
all results in excess of the specified limit but within this 
permissible variation shall be reported as .85 per cent. 

Sulphuric Anhydride 

24. One gram of the cement shall be dissolved in 5 
c.c. of concentrated hydrochloric acid diluted with 5 c.c. 
of water, with gentle warming; when solution is complete 
40 c.c. of water shall be added, the solution filtered, and 
the residue washed thoroughly with water. The solution 
shall be diluted to 250 c.c., heated to boiling and 10 c.c. 
of a hot 10-per cent, solution of barium chloride shall 
be added slowly, drop by drop, from a pipette and the 
boiling continued until the precipitate is well formed. 
The solution shall be digested on the steam bath until 
the precipitate has settled. The precipitate shall be 
filtered, washed, and the paper and contents placed in a 
weighed platinam crucible and the paper slowly charred 
and consumed without flaming. The barium sulfate 
shall then be ignited and weighed. The weight ob- 
tained multiplied by 34.3 gives the percentage of sulfuric 
anhydride. The acid filtrate obtained in the determina- 
tion of the insoluble residue may be used for the estima- 
tion of sulfuric anhydride instead of using a separate 
sample. 

25. A permissible variation of 0.10 will be allowed, and 
all results in excess of the specified limit but within this 
permissible variation shall be reported as 2.00 per cent. 

Magnesia 

26. To 0.5 g. of the cement in an evaporating dish shall 
be added 10 c.c. of water to prevent lumping and then 10 
c.c. of concentrated hydrochloric acid. The liquid 



80 LABORATORY MANUAL OF TESTING MATERIALS 

shall be gently heated and agitated until attack is 
complete. The solution shall then be evaporated to 
complete dryness on a steam or water bath. To hasten 
dehydration the residue may be heated to 150 or even 
2dOC. for one-half to one hour. The residue shall be 
treated with 10 c.c. of concentrated hydrochloric acid 
diluted with an equal amount of water. The dish shall 
be covered and the solution digested for ten minutes on 
a steam bath or water bath. The diluted solution 
shall be filtered and the separated silica washed thor- 
oughly with water. 1 Five cubic centimeters of concen- 
trated hydrochloric acid and sufficient bromine water to 
precipitate any manganese which may be present, shall 
be added to the filtrate (about 250 c.c.). This shall be 
made alkaline with ammonium hydroxide, boiled until 
there is but a faint odor of ammonia, and the precipitated 
iron and aluminum hydroxides, after settling, shall be 
washed with hot water, once by decantation and slightly 
on the filter. Setting aside the filtrate, the precipitate 
shall be transferred by a jet of hot water to the precipi- 
tating vessel and dissolved in 10 c.c. of hot hydrochloric 
acid. The paper shall be extracted with acid, the solution 
and washings being added to the main solution. The 
aluminum and iron shall then be reprecipitated at 
boiling heat by ammonium hydroxide and bromine 
water in a volume of about 100 c.c., and the second 
precipitate shall be collected and washed on the filter 
used in the first instance if this is still intact. To the 
combined filtrates from the hydroxides of iron and alumi- 
num, reduced in volume if need be, 1 c.c. of ammonium 
hydroxide shall be added, the solution brought to boiling, 
25 c.c. of a saturated solution of boiling ammonium 

1 Since this procedure does not involve the determination of 
silica, .1 second evaporation is unnecessary. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 81 

oxalate added, and the boiling continued until the precipi- 
tated calcium oxalate has assumed a well-defined granu- 
lar form. The precipitate after one hour shall be filtered 
and washed, then with the filter shall be placed wet in 
a platinum crucible, and the paper burned off over a 
small flame of a Bunsen burner; after ignition it shall 
be redissolved in hydrochloric acid and the solution 
diluted to 100 c.c. Ammonia shall be added in slight 
excess, and the liquid boiled. The lime shall then be 
reprecipitated by ammonium oxalate, allowed to stand 
until settled, filtered and washed. The combined 
filtrates from the calcium precipitates shall be acidified 
with hydrochloric acid, concentrated on the steam bath 
to about 150 c.c., and made slightly alkaline with am- 
monium hydroxide, boiled and filtered (to remove a little 
aluminum and iron and perhaps calcium). When cool, 
10 c.c. of saturated solution of sodium-ammonium- 
hydrogen phosphate shall be added with constant 
stirring. When the crystallin ammonium-magnesium 
orthophosphate has formed, ammonia shall be added in 
moderate excess. The solution shall be set aside for 
several hours in a cool place, filtered and washed with 
water containing 2.5 per cent, of NH 3 . The precipitate 
shall be dissolved in a small quantity of hot hydro- 
chloric acid, the solution diluted to about 100 c.c., 1 c.c. 
of a saturated solution of sodium-ammonium-hydrogen 
phosphate added, and ammonia drop by drop, with 
constant stirring, until the precipitate is again formed 
as described and the ammonia is in moderate excess. 
The precipitate shall then be allowed to stand about two 
hours, filtered and washed as before. The paper and 
contents shall be placed in a weighed platinum crucible, 
the paper slowly charred, and the resulting carbon care- 
fully burned off. The precipitate shall then be ignited 



82 LABORATORY MANUAL OF TESTING MATKIMAI/* 

to constant weight over a Meker burner, or a blast not 
strong enough to soften or melt the pyrophosphate. 
The weight of magnesium pyrophosphate obtained 
multiplied by 72.5 gives the percentage of magnesia. 
The precipitate so obtained always contains some cal- 
cium and usually small quantities of iron aluminum, and 
manganese as phosphates. 

27. A permissible variation of 0.4 will be allowed, and 
all results in excess of the specified limit but within this 
permissible variation shall be reported as 5.00 per cent. 

VIII. DETERMINATION OF SPECIFIC GRAVITY 

28. The determination of specific gravity shall be mude 
with a standardized Le Chatelier apparatus which con- 
forms to the requirements illustrated in Fig. I. 1 This 
apparatus is standardized by the United States Bureau 
of Standards. Kerosene free from water, or benzine not 
lighter than 62 Baume, shall be used in making this 
determination. 

29. The flask shall be filled with either of these liquids 
to a point on the stem between zero and 1 c.c., and 
64 g. of cement, of the same temperature as the liquid, 
shall be slowly introduced, taking care that the cement 
does not adhere to the inside of the flask above the 
liquid and to free the cement from air by rolling the 
flask in an inclined position. After all the cement is 
introduced, the level of the liquid will rise to some divi- 
sion of the graduated neck; the difference between read- 
ings is the volume displaced by 64 g. of the cement. 

The specific gravity shall then be obtained from the 

formula 

Weight of cement (g.) 
Specific gravity = Disp] - ced ; volume (c ; c .) 

1 American Society for Testing Materials, Standards 1918, 
page 511. 



INSTRUCTIONS FOR 1'KRFORMING EXPERIMENTS 83 

30. The flask, during the operation, shall be kept im- 
mersed in water, in order to avoid variations in the tem- 
perature of the liquid in tihe flask, which shall not exceed 
0.5 C. The results of repeated tests should agree within 
0.01. 

31. The determination of specific gravity shall be made 
on the cement as received; if it falls below 3.10, a second 
determination shall be made after igniting the sample as 
described in Section 20. 

IX. DETERMINATION OF FINENESS 
Apparatus 

32. Wire cloth for standard sieves for cement shall be 
woven (not twilled) from brass, bronze, or other suitable 
wire, and mounted without distortion on frames not less 
than 1J2 in. below the top of the frame. The sieve 
frames shall be circular, approximately 8 in. in diameter, 
and may be provided with a pan and cover. 

33. A standard No. 200 sieve is one having nominally 
an 0.0029-in. opening and 200 wires per inch standardized 
by the U. S. Bureau of Standards, and conforming to the 
following requirements : 

The No. 200 sieve should have 200 wires per inch, and 
the number of wires in any whole inch shall not be outside 
the limits of 192 to 208. No opening between adjacent 
parallel wires shall be more than 0.0050 in. in width. 
The diameter of the wire should be 0.0021 in. and the 
average diameter shall not be outside the limits 0.0019 to 
0.0023. The value of the sieve as determined by sieving 
tests made in conformity with the standard specification 
for these tests on a standardized cement which gives a 
residue of 25 to 20 per cent, on the No. 200 sieve, or on 
other similarly graded material, shall not show a varia- 



84 LABORATORY MANUAL OF TESTING MATERIALS 

tion of more than 1.5 per cent, above or below the stand- 
ards maintained at the Bureau of Standards. 

Method 

34. The test shall be made with 50 g. of cement. The 
sieve shall be thoroughly clean and dry. The cement 
shall be placed on the No. 200 sieve, with pan and cover 
attached, if desired, and shall be held in one hand in a 
slightly inclined position so that the sample will be well 
distributed over the sieve, at the same time gently strik- 
ing the side about 150 times per minute against the palm 
of the other hand on the up stroke. The sieve shall be 
turned every 20 strokes about one-sixth of a revolution 
in the same direction. The operation shall continue until 
not more than 0.05 g. passes through in one minute of 
continuous sieving. The fineness shall be determined 
from the weight of the residue on the sieve expressed as a 
percentage of the weight of the original sample. 

35. Mechanical sieving devices may be used, but the 
cement shall not be rejected if it meets the fineness re- 
quirement when tested by the hand method described in 
Section 34. 

36. A permissible variation of 1 will be allowed, and all 
results in excess of the specified limit but within this per- 
missible variation shall be reported as 22 per cent. 

X. MIXING CEMENT PASTES AND MORTARS 

37. The quantity of dry material to be mixed at one 
time shall not exceed 1000 g. nor be less than 500 g. The 
proportions of cement or cement and sand shall be stated 
by weight in grams of the djry materials; the quantity of 
water shall be expressed in cubic centimeters (1 c.c. of 
water =1 g.). The dry materials shall be weighed, 



INSTRUCTIONS FOR PERFORMING EXPKRIMENTS 85 

placed upon. a non-absorbent surface, thoroughly mixed 
dry if sand is used, and a crater formed in the center, into 
which the proper percentage of clean water shall be 
poured; the material on the outer edge shall be turned 
into the crater by the aid of a trowel. After an interval 
of Yi minute for the absorption of the water the operation 
shall be completed by continuous, vigorous mixing, 
squeezing and kneading with the hands for at least one 
minute. 1 During the operation of mixing, the hands 
should be protected by rubber gloves. 

38. The temperature of the room and the mixing water 
shall be maintained as nearly as practicable at 21C. 
(70F.). 

XI. NORMAL CONSISTENCY 

39. The Vicat apparatus consists of a frame A, Fig. 2, 
page 514, Year Book 1918 bearing a movable rod B, 
weighing 300 g., one end C being 1 cm. in diameter for 
a distance of 6 cm., the other having a removable needle 

D, 1 mm. in diameter, 6 cm. long. The rod is reversible, 
and can be held in any desired position by a screw 

E, and has midway between the ends a mark F which 
moves under a 'scale (graduated to millimeters) attached 
to the frame A. The paste is held in a conical, hard- 
rubber ring G, 7 cm. in diameter at the base, 4 cm. high, 
resting on a glass plate H about 10 cm. square. 

40. In making the determination, 500 g. of cement, 
with a measured quantity of water, shall be kneaded into 

1 In order to secure uniformity in the results of tests for the time 
of setting and tensile strength the manner of mixing above de- 
scribed should he carefully followed. At least one minute is 
necessary to obtain the desired plasticity which is not appreciabty 
affected by continuing the mixing for several minutes. The exact 
time necessary is dependent upon the personal equation of the 
operator. The error in mixing should be on the side of over 
mixing. 



86 



LABORATORY MANUAL OF TESTING MATERIALS 



a paste, as described in Section 37, and quickly formed 
into a ball with the hands, completing the operation by 
tossing it six times from one hand to the other, main- 
tained about 6 in. apart; the ball resting in the palm of 
one hand shall be pressed into the larger end of the 
rubber ring held in the other hand, completely filling 
the ring with paste; the excess at the larger end shall 
then be removed by a single movement of the palm of 
the hand; the ring shall then be placed on its larger end 
on a glass plate and the excess paste at the smaller end 
sliced off at the top of the ring by a single oblique stroke 
of a trowel held at a slight angle with the top of the ring. 

PERCENTAGE OF WATER FOR STANDARD MORTARS 



Percentage of 
water for 
neat cement 
pa^te of 
normal 
consistency 

15 


Percentage of water 
for one cement, 
three standard 
Ottawa sand 


Percentage of water 
for neat cement 
paste of normal 
consistency 


Percentage of water 
for one cement, 
three standard 
Ottawa sand 


9.0 


1 

23 10.3 


16 


9.2 


24 10.5 


17 


9.3 


25 


10.7 


18 


9.5 


26 


10.8 


19 


9.7 


27 


11.0 


20 


9.8 


28 


11.2 


21 


10.0 


29 


11.3 


22 


10.2 

1 


30 


11.5 



During these operations care shall be taken not to com- 
press the paste. The paste confined in the ring, resting 
on the plate, shall be placed under the rod, the larger 
end of which shall be brought in contact with the surface 
of the paste; the scale shall be then read, and the rod 
quickly released. The paste shall be of normal consis- 
tency when the rod settles to a point 10 mm. below the 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 87 

original surface in % minute after being released. The 
apparatus shall be free from all vibrations during the 
test. Trial pastes shall be made with varying percent- 
ages of water until the normal consistency is obtained. 
The amount of water required shall be expressed in 
percentage by weight of the dry cement. 

41. The consistency of standard mortar shall depend 
on the amount of water required to produce a paste of 
normal consistency from the same sample of cement. 
Having determined the normal consistency of the sample, 
the consistency of standard mortar made from the same 
sample shall be as indicated in Table I, the values being 
in percentage of the combined dry weights of the cement 
and standard sand. 

XII. DETERMINATION OF SOUNDNESS 1 

42. A steam apparatus, which can be maintained at a 
temperature between 98 and 100C., or one similar to 
that shown in Fig. 3, Standards Amer. Soc. for Test. 
Materials, 1918, p. 516 is recommended. The capacity 
of this apparatus may be increased by using a rack for 
holding the pats in a vertical or inclined position. 

43. A pat from cement paste of normal consistency 
about 3 in. in diameter, ^ in. thick at the center, and 
tapering to a thin edge, shall be made on clean glass 
plates about 4 in. square, and stored in moist air for 24 

1 Unsoundness is usually manifested by change in volume which 
causes distortion, cracking, checking or disintegration. 

Pats improperly made or exposed to drying may develop what 
are known as shrinkage cracks within the first 24 hours and are 
not an indication of unsoundness. These conditions are illustrated 
in Fig. 4. See American Society for Testing Materials, page 517. 

The failure of the pats to remain on the glass or the cracking of 
the glass to which the pats are attached does not necessarily indi- 
cate unsoundness. 



88 LABORATORY MANUAL, OF TESTING MATERIALS 

hours. In molding the pat, the cement paste shall first 
be flattened on the glass and the pat then formed by 
drawing the trowel from the outer edge toward the center. 

44. The pat shall then be placed in an atmosphere of 
steam at a temperature between 98 and 100C. upon a 
suitable support 1 in. above boiling water for 5 hours. 

45. Should the pat leave the plate, distortion may be 
detected best with a straight edge applied to the surface 
which was in contact with, the plate. 

XIII. DETERMINATION OF TIME OF SETTING 

46. The following are alternate methods, either of 
which may be used as ordered : 

47. The time of setting shall be determined with the 
Vicat apparatus described in Section 39. 

48. A paste of normal consistency shall be molded in 
the hard-rubber ring G as described in Section 40, and 
placed under the rod B, the smaller end of which shall 
then be carefully brought in contact with the surface of 
the paste, and the rod quickly released. The initial 
set shall be said to have occurred when the needle 
ceases to pass a point 5 mm. above the glass plate in Y^ 
minute after being released; and the final set, when the 
needle does not sink visibly into the paste. The test 
pieces shall be kept in moist air during the test. This 
may be accomplished by placing them on a rack over 
water contained in a pan and covered by a damp cloth 
kept from contact with them by means of a wire screen; 
or they may be stored in a moist closet. Care shall be 
taken to keep the needle clean, as the collection of cement 
on the sides of the needle retards the penetration, while 
cement on the point may increase the penetration. The 
time of setting is affected not only by the percentage and 
temperature of the water used and the amount of knead- 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 89 

ing the paste receives, but by the temperature and humid- 
ity of the air, and its determination is therefore only 
approximate. 

49. The time of setting shall be determined by the 
Gillmore needles. The Gillmore needles should prefer- 
ably be mounted as shown in Fig. 5 (6). 1 

50. The time of setting shall be determined as follows : 
A pat of neat cement paste about 3 in. in diameter and 
12 in. in thickness with a flat top (Fig. 5 (a)), 2 mixed to a 
normal consistency, shall be kept in moist air at a tem- 
perature maintained as nearly as practicable at 21C. 
(70F.). The cement shall be considered to have 
acquired its initial set when the pat will bear, without 
appreciable indentation, the Gillmore needle ^{2 i n - in 
diameter, loaded to weigh J^ Ib. The final set has been 
acquired when the pat will bear without appreciable 
indentation, the Gillmore needle ^4 in. in diameter, 
loaded to weigh 1 Ib. In making the test the needles 
shall be held in a vertical position, and applied lightly to 
the surface of the pat. 

XIV. TENSION TESTS 

51. The form of test piece shown in Fig. 6 1 shall be 
used. The molds shall be made of non-corroding metal 
and have sufficient material in the sides to prevent 
spreading during molding. Gang molds when used 
shall be of the type shown in Fig. 7. 3 Molds shall be 
wiped with an oily cloth before using. 

52. The sand to be used shall be natural sand from 
Ottawa, 111., screened to pass a No. 20 sieve, and retained 

1 Standards, 1918, Amer. Soc. for Test. Materials, p. 519. 

2 Standard 1918, Amer. Soc. for Test. Materials, p. 519. 

3 See 1918 Standards, Amer. Soc. for Testing Materials, p. 
520, 521. 



90 LABORATORY MANUAL OF TESTING MATERIALS 

on a No. 30 sieve. This sand may be obtained from 
the Ottawa Silica Co., at a cost of two cents per pound, 
f.o.b. cars, Ottawa, 111. 

53. This sand, having passed the No. 20 sieve, shall 
be considered standard when not more than 5 g. pass 
the No. 30 sieve after one minute continuous sieving of a 
500-g. sample. 

54. The sieves shall conform to the following specifica- 
tions : 

The No. 20 sieve shall have between 19.5 and 20.5 
wires per whole inch of the warp wires and between 19 
and 21 wires per whole inch of the shoot wires. The 
diameter of the wire should be 0.0165 in. and the average 
diameter shall not be outside the limits of 0.0160 and 
0.0170 in. 

The No. 30 sieve shall have between 29.5 and 30.5 
wires per whole inch of the warp wires and between 
28.5 and 31.5 wires per whole inch of the shoot wires. 
The diameter of the wire should be 0.0110 in. and the 
average diameter shall not be outside the limits 0.0105 
to 0.01 15 in. 

55. Immediately after mixing, the standard mortar 
shall be placed in the molds, pressed in firmly with the 
thumbs and smoothed off with a trowel without ram- 
ming. Additional mortar shall be heaped above the 
mold and smoothed off with a trowel; the trowel shall 
be drawn over the mold in such a manner as to exert a 
moderate pressure on the material. The mold shall 
then be turned over and the operation of heaping, thumb- 
ing and smoothing off repeated. 

56. Tests shall be made with any standard machine. 
The briquettes shall be tested as soon as they are re- 
moved from the water. The bearing surfaces of the 
clips and briquettes shall be free from grains of sand or 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 91 

dirt. The briquettes shall be carefully centered and 
the load applied continuously at the rate of 600 Ib. per 
minute. 

57. Testing machines should be frequently calibrated 
in order to determine their accuracy. 

58. Briquettes that are manifestly faulty, or which 
give strengths differing more than 15*per cent, from the 
average value of all test pieces made from the same 
sample and broken at the same period, shall not be 
considered in determining the tensile strength. 

XV. STORAGE OF TEST PIECES 

59. The moist closet may consist of a soapstone, slate 
or concrete box, or a wooden box lined with metal. If a 
wooden box is used, the interior should be covered with 
felt or broad wicking kept wet. The bottom of the 
moist closet should be covered with water. The interior 
of the closet should be provided with non-absorbent 
shelves on which to place the test pieces, the shelves 
being so arranged that they may be withdrawn 
readily. 

60. Unless otherwise specified all test pieces, immedi- 
ately after molding, shall be placed in the moist closet 
for from 20 to 24 hours. 

61. The briquettes shall be kept in molds on glass 
plates in the moist closet for at least 20 hours. After 24 
hours in moist air the briquettes shall be immersed 
in clean water in storage tanks of non-corroding 
material. 

62. The air and water shall be maintained as nearly as 
practicable at a temperature of 21C. (70F.). 



92 LAUOHATOHY MANUAL OF TESTING MATERIALS 

Experiment D-7 

STRENGTH OF CEMENT MORTARS IN COMPRESSION 

This experiment will give the quality of a cement as 
shown by compression tests of standard Ottawa sand 
mortars. 

References. Proc. Amer. Soci for Testing Materials, 
1919, Part I. 

Hool and Johnson Handbook, page 10. 

Mills Material of Construction, page 164 . 

Material : Any brand of cement. 

Special Apparatus: At least six cylindrical molds, 2 in. 
in diameter and 4 in. in height. Standard metal tam- 
per 1 in. in diameter and % Ib. in weight. 

Procedure. Using standard Ottawa sand mix a 1 to 
3 mortar of Normal Consistency. (See Table, p. 86). 

NOTE. If sufficient mortar for six 2 by 4-in. cylinders 
is to be mixed in a single batch, 750 g. of cement and 
2250 g. of standard sand will be required.. In this case 
the mixing shall be continued for 1^ minutes. (See 
standard methods of mixing and molding, page 84.) 
Place the empty mold on an oiled glass plate and fill 
with the mortar in layers of 1 in. tamping each layer 
with the standard metal tamper. The top should be 
carefully finished by heaping up the mortar and smooth- 
ing off with the trowel. An oiled glass cover plate 
should be placed on top and remain until molds are 
removed (after 1 day storage in moist air). 

Test the specimens at the end of 6 and 27 days' storage 
in water. The testing machine should be capable of 
applying the load continuously and uniformly to failure. 
The moving head of the testing machine shall travel 
at the rate of not less than 0.05 or more than 0.10 in. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 



93 



per minute. During the test, a spherical bearing 
block, accurately centered, shall be used on top of the 
cylinder. 

Report : Follow the standard form on page 7. 

TABLE ON UNIT STRESSES FOR LOADS ON 2-iN. CYLINDERS (3.14 

SQ. IN.) 



Total load 
Unit stress 




10 
3 


20 
6 


30 40 
10 13 


50 
16 


60 
19 


70 
22 


80 
25 


90 
29 


Total load (lb.)- 


000 


100 


200 


300' 400 


500 


600 


700 


800 


900 



Unit stress (lb. per sq. in.) 



0000 




32 


64 


95 127 


159 


191 


223 


255 


286 


1000 j 318 


350 


382 


413' 445 


477 


509 


541 


573 


604 


2000 


637 


669 


701 


732 764 


796 


828 


860 


892 


923 


3000 


955 


987 


1019 


1050 1082 


1114 


1146 


1178 


1210 


1241 


4000 


1273 


1305 


1337 


13681 1400 


1432 


1464 


1496 


1528 


1559 


5000 


1592 


1624 


1656 1687 1719 


1751 


1783 


1815 


1847 


1878 


6000 


1910 


1942 


1974 


2005 


2037 


2069 


2101 


2133 


2165 


2196 


7000 


2228 


2260 


2292i 2323 


2355 


2387 


2419 


2451 


2483 


2514 


8000 


2546 


2578 


2610 2641 


2673 


2705 


2737 


2769 


2801 


2832 


9000 


2865 


2897 


2929 


2960 


2992 


3024 


3056 


3088 


3120 


3151 



Article 5 

STUDY OF AGGREGATES 

Notes on the Sampling of Aggregates Used in Con- 
crete Construction. The value of tests of the constituent 
materials entering into a concrete construction depend 
almost entirely upon whether the samples obtained are 
thoroughly representative of the aggregates used. 

When it is positively certain that the material sampled 
is the material shipped and used in the construction then 
the samples may be taken at the pit or quarry. When 
there is uncertainty as to this point, samples for test 



94 LABORATORY MANUAL OF TESTING MATERIALS 

should be taken from shipments as they arrive where they 
are to be used. 

SAMPLING OF STONE FROM LEDGES OR QUARRIES FOR 
QUALITY 

Inspect ledge or quarry face closely to determine any 
variation in different layers. Observe any difference in 
color or structure, and if necessary to secure unweathered 
specimens, break pieces from different layers. 

For standard stone test take separate samples of at 
least 30 ,lb. each of fresh unweathered specimens from all 
layers that appear to vary in color or structure. When 
more than one piece is taken, the minimum size shall be 
2 in., except that there shall be one piece of a minimum 
size of 4 in. X 5 in. X- 3 in. on which the bedding plane 
is marked. This latter piece shall be free from seams or 
fractures as it is used in the toughness or compression 
test. 

The size of sample for concrete test will have to have 
special instruction as it depends on the kind of tests to be 
made and the number of specimens necessary. 

SAMPLING OF GRAVEL OR SAND 

Sampling at a pit which has exposed vertical faces may 
be done by scooping out a small uniform vertical channel 
from bottom to top of faces. If the material excavated 
from this channel is more than desired it may be reduced 
by the method of quartering. Samples taken in this way 
from the various faces of a pit should be kept separate 
with the proper identification as to location, inasmuch as 
it may happen that some parts of the same bank may 
yield an undesirable material. 

The pit should be carefully examined before selecting 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 95 

the location of a sample. It frequently happens that a 
bank is not of a homogeneous mixture throughout and 
that layers or pockets are found in which is a material of 
of uniform size or perhaps of clay. Boulders may be 
present in one section and not in another. If the pit is a 
large one more than one sample must be taken to properly 
represent the deposit. 

Deposits that have no open face shall be sampled by 
means of test pits. The number and depth of these will 
depend on local conditions and the amount of material to 
be used from the source. 

Sampling the aggregate after it has arrived on the job 
may be done by collecting and mixing a small quantity 
from many different parts of the pile, or bin. These 
small quantities should be obtained by digging into the 
pile not by collecting what rolls down the outside as that 
is likely to be composed of only the coarser particles. 
The test samples themselves should always be acquired 
from the larger samples by the method of quartering. 

Quartering. To quarter a sample of Aggregate it is 
spread out on a clean flat surface in the form of a circular 
disc of uniform thickness. Care should be taken that 
particles of different size are distributed through the 
mass. The material is then divided into four quarters 
and two opposite quarters removed completely. The 
remaining quarters are then mixed together and the 
operation repeated. This is done until the quantity 
remaining is the size required for the experiment. 

Shipping and Storing of Samples. The samples 
should be shipped and stored in such a way as to retain 
as much as possible of the natural moisture of the 
material. 



90 LABORATORY MANUAL OF TESTING MATERIALS 

Experiment E-2 
TEST OF SAND FOR CLEANNESS 

References. Engineering News, Feb. 4, 1915, page 204. 

Engineering Record, Jan. 8, 1916, pages 48 and 49. 

Abrams-Harder Field test for Organic Impurities in 
Sands, Proc. Amer. Soc. for Testing Materials, Vol. 
XIX, Part 1, 1919. 

Comment. The impurities in sand are: (1) Silt, the 
fine scum that settles on sand that has. been shaken in 
water. Silt may contain organic matter, such as loam, 
sugar, sewage, that may prevent concrete from harden- 
ing. (2) Clay, an inorganic, fine material that may 
assist in filling up the pores in a clean concrete. 

A dirty sand will stain the palm of the hand, but- 
specific tests should be made: 

1. Method of Washing. Dry a 220 gram sample 
obtained by quartering and at room temperature to 
avoid baking the clay. Extra care must be taken in 
dividing the material after drying to prevent separation 
of fine from coarse. Weigh 200 grams on the 100 sieve, 
soak in water to soften any lumps; wash on the sieve 
in a gentle stream of water; dry under a gas burner, 
and reweigh. Per cent, of silt is loss in weight divided 
by 200 and multiplied by 100. 

2. Method of Decantation or Elutriation (for field use) . 
Place 20 c.c. of sand, obtained by quartering, in a 100 c.c. 
cylinder with 30 c.c. of lukewarm water. Stir with u 
wire for 30 seconds; allow to settle for 30 seconds. 
Decant water in a second 100 c.c. cylinder. Stir up 
sand in 1st. cylinder with fresh portion of water, and 
repeat process 3 times. Settle the two cylinders for 
1 hour. Note silt in cylinder L No, 2 and sand in 
Cylinder No. 1, 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 97 

Per cent, of Silt = 

Number of c.c. in Cyl. No. 2 y 100 

c7c. of silt in Cyf. No. 2 + c.c. of sand in No. 1 

A more accurate expression is perhaps obtained by 
dividing amount of silt by original volume of sand. 

NOTE. A rough method is to stir up sand in Cyl. No. 
1 and allow silt to settle on top. Measure height of 
sand and of silt on top. 

NOTE. The per cent, of silt by volume is from one to 
two times the per cent, by weight. 

3. Silt Determination of Road Sands and Gravel. 



PROPOSED TENTATJVE TEST, AMER. Soc. FOR 
TESTING MATERIALS 1920 

1. Scope. This test covers the determination of the 
quantity of clay and silt in natural sands and gravel 
to be used in highway construction. 

2. Treatment of Sample. The sample as received 
shall be moistened and thoroughly mixed, then dried to 
constant weight at a temperature between 100 and 
110C. (212 and230F.) 

3. Method. A representative portion of the dry 
material, weighing 500 g. for sand and not less than 50 
times the weight of the largest stone in the sample for 
gravel shall be selected from the sample, and placed in a 
dried and accurately weighed pan or vessel. The pan 
shall be 12 in. (30.2 cm.) in diameter by not less than 
4 in. (10.2 cm.) deep, as nearly as may be obtained. 
Pour sufficient water in the pan to cover the gravel and 
agitate vigorously for 15 seconds, using a trowel or 
stirring rod. Allow to settle for 15 seconds, and then 
pour off the water into a tared evaporating dish, taking 



98 LABORATORY MANUAL OF TESTING MATERIALS 

care not to pour off any gravel. Repeat until the wash 
water is clear. Dry the washed material to constant 
weight in an oven at a temperature between 100 and 
110C. (212 and 230F.), weigh, and determine the net 
weight of gravel. 

The percentage of clay and silt shall be calculated 
from the formula: 

Percentage of Clay and Silt = 

Original weight weight after washing 
Original weight 

For a check on the results, evaporate the wash water 
to dryness and weigh the residue: 



4. Test for Organic Matter. Organic matter in the 
silt is determined by the Colorimetric Test. 

Fill a 12 oz. prescription bottle to the 4J/2 oz. mark with 
the sand to be tested, then add 3 per cent, solution of 
sodium hydroxide until the bottle is filled to the 7 oz. 
mark. Allow mixture to stand over night and then 
examine color of liquid above sand. A very dark orange 
is objectionable, a dark brown or black color indicates 
that the sand is badly contaminated, while a white or 
light yellow color indicates that there is little organic 
impurity present. 

NOTE Proportionate amounts may be used and the 
test made in any clear glass container. 

5. Strength Test of Mortars. A common test for sand 
is in a mortar briquette as indicated in the specifications 
below. Note that fine soft limestone dust from quarry 
screenings may cause failure in a structure, without 
showing defects in this test. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 99 

FINE AGGREGATE FOR CLASS "A" CONCRETE 

Strength. Mortar composed of one (1) part, by 
weight, of Portland cement and three (3) parts, by weight, 
of sand* mixed in accordance with methods referred to 
in Page 84 shall have a tensile strength at the age of 
seven (7) and twenty-eight (28) days of not less than 
one hundred (100) per cent, of that developed by mortar 
of the same proportions and consistency, made of the 
same cement and standard Ottawa sand. In testing 
aggregates care should be exercised to avoid the removal 
of any coating on the grains, which may affect the 
strength; bank sands should not be dried before being 
made into mortar, but should contain natural moisture. 
The percentage of moisture may be determined upon a 
separate sample for correcting weight. From 10 to 40 
per cent, more water may be required in mixing bank or 
artificial sands than for standard Ottawa sand to produce 
the same consistency. 

Experiment. Select 5 samples of sand to include 
Ottawa Sand; bank sand; same sand washed; sand 
containing loam, limestone screenings. Apply the 
4 tests and report which sands are suitaible for use in 
concrete. Has the strength test indicated the cleanness 
of the sand. 

Experiment E-3 

WEIGHT OF AGGREGATES 

The weight per cubic foot gives a close estimate of the 
value of sand or other aggregate. 

Some general considerations must be understood in 
this experiment. 

Sizing. The weight per cubic foot of sand or of peb- 
bles of graded sizes would be greater than if of uniform 



100 



LABORATORY MANUAL OF TESTING MATERIALS 



size. Why? Likewise the weight per cubic foot of the 
mixture of the fine and coarse aggregate will be greater 
than of either alone. 

The volume produced by mixing a cubic foot of coarse 
aggregate with a cubic foot of fine aggregate will be less 
than 2 cu. ft., about 1%. 

Moisture. A film of water forces sand particles apart. 
Therefore dry sand swells when damp and weighs less 
per cubic foot. The amount of the swelling depends 




25 



0123456789 
Moisture Per Cent by Weight 

FIG. 28. Voids in sand and gravel when moisture and unit 
weight are known. 

upon (a) the amount of water; and (6) the fineness of 
the sand. The maximum bulking effect in sand occurs 
at a "per cent, of water from 5 to 6 per cent, by weight, 
and is 30 per cent, for fine sand, 25 per cent, for medium 
sand, and 20 per cent, for coarse sand. Pebbles are 
only slightly affected. 1 per cent, of water may in- 



INSTRUCTIONS FOR PERFORMING tia&tWKiU$1t9' J * i i \ 101 

crease the volume of fine sand 10 to 15 per cent. As the 
amount of water increases, filling the voids, a flood stage 
is reached and the sand return to its former dry volume. 
For Example Coarse Sand: dry, 107^ Ib. per cu. 
ft.; wet, with 3 per cent, of water, 94 Ib. per cu. ft. 
Medium Sand: dry, 99 J-^ Ib. per cu. ft; wet with 
5 per cent, of water, 90 Ib. per cu. ft. Above cases 
are for compacted sand. When sand that has been in 
a rain storm is re-shoveled in a loose pile, the increase in 
volume may be % to J^ more. 

Evidently the test for weight per cubic foot must be 
standard as to moisture and compacting. 

DETERMINE THE WEIGHT PER CUBIC FOOT BY STANDARD 
ROD METHOD 

Measure Rod 

100 c.c .................................. }-i inch X 18 inches. 

1000 c.c ................................. y inch X 18 inches. 

H cu. ft ........................... , ..... y 2 inch X 18 inches. 

1 cu. ft ................................. inch x 18 inches. 



The Rod method is operated as follows: 

Fill the measure one-third full of the aggregate, then, 
with a pointed iron rod of a prescribed size, jab or puddle 
the aggregate twenty-five times, distributing the strokes 
over the surface of the aggregate and avoiding penetrat- 
ing through the layer of aggregate so as to hit the bottom 
of the measure. Then add another one-third to the 
contents of the measure and again jab with the iron rod 
twenty-five times, penetrating only the last layer of 
aggregate placed in the measure. Next, fill the measure 
to overflowing and repeat the jabbing, then strike off 
the surplus sand with the iron rod and weigh. 



.102 



'MANUAL OF TESTING MATERIALS 



THE PROPOSED TENTATIVE TEST FOR UNIT WEIGHT OF 

AGGREGATES, AMER. Sot. FOR TESTING 

MATERIALS 1920 

Measures. The measure shall be of metal, preferably 
machined to accurate dimensions on the inside, cylindri- 
cal in form, watertight, and of sufficient rigidity to 
retain its form under rough usage, with top and bottom 
true and even, and preferably provided with handles. 

The measure shall be of Ko> % or 1 cu. ft. capacity, 
depending on the maximum diameter of the coarsest 
particles in the aggregate, and shall be of the following 
dimensions : 



Capacity, 
cu. ft. 


Inside 
diameter, 
in. 


Inside 
neight, 
in. 


Minimum 
thickness 
of metal, 
U.S. gage 


Diameter of 
largest 
particles of 
aggregate, in. 


Ko 


6 00 


6 10 


No. 11 


Under ^ 


y 2 


10.00 


11.00 


No. 8 


Under 1> 


i 


14.00 


11.23 


No. 5 


Over iy 2 



Tamping Rod. The tamping rod shall be a straight 
metal rod % m - m diameter and 18 in. long, with one end 
tapered for a distance of 1 in. to a blunt bullet-shape 
point. 

Report the weight per cubic foot of the several sands 
provided by Instructor to include : 

Medium Sand: (a) dry, (6) with 5 per cent, water; 
Ottawa Sand; Mixed fine and coarse gravel aggregate; 
bank run gravel; crushed stone. 

If the specific gravity and voids of these have been 
determined by previous experiments, report the extent to 
which these weights are a measure of the voids. 

Problems. The Air Dry Sand, (a) is bought by the 
ton to be used in a 1-2-4 concrete proportioned by 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 103 

volume. It becomes damp through exposure as in (6). 
Report the additional amount of sand (6) that should 
be used in mixing the concrete. 

Freight charges are paid for sand by the ton. What 
would be the proportionate amounts of freight charges 
on a car load of sand (a) dry and (6) damp with 5 per 
cent, water. 

Experiment E-4 

THE SPECIFIC GRAVITY OF VARIOUS MATERIALS USED 
AS AN AGGREGATE IN CONCRETE 

Object. The object of this test is to determine the 
specific gravity of the various materials used as an aggre- 
gate in concrete. 

References. Taylor & Thompson, pages 122 to 123. 
Concrete Engineer's Handbook Hool & Johnson, p. 25. 

Materials. The following materials will be used: 
sand or gravel, stone. A porous material should first 
be moistened to fill the pores and the surfaces of the par- 
ticles be dried by means of blotting paper. A correction 
for the weight of absorbed moisture can be made by dry- 
ing the material in an oven. 

American Society for Testing Materials Standard 
Tests are as follows : 

1. Fine Aggregates. 

(a) Le Chatelier Test using approx. 64 g. of mate- 
rial as in test for cement except that liquid may be 
water or kerosene. 

(6) Jackson Test using about 55 g. of material in 
the following apparatus : 

The determination shall be made with a Jackson 
specific gravity apparatus, which shall consist of a 
burette, with graduations reading to 0.01 in specific 



104 LABORATORY MANUAL OF TESTING MATERIALS 

gravity, about 23 cm. (9 in.) long and with an inside 
diameter of about 0.6 cm. (0.25 in.), which shall be con- 
nected with a glass bulb approximately 13 cm. (5.5 in.) 
long and 4.5 cm. (1.75 in.) in diameter, the glass bulb 
being of such size that from a mark on the neck at the 
top to a mark on the burette just below the bulb, the 
capacity is exactly 180 c.c. (6.09 liquid oz.); and an 
Erlenmeyer flask, which shall contain a hollow ground- 
glass stopper having the neck of the same bore as the 
burette, and shall have a capacity of exactly 200 c.c. 
(6.76 oz.) up to the graduation on the neck of the 
stopper. 

2. Coarse Aggregates. The apparent specific gravity 
shall be determined in the following manner : 

1. The sample, weighing 1000 g. and composed of 
pieces approximately cubical or spherical in shape and 
retained on a screen having 1.27-cm. (J^-in.) circular 
openings, shall be dried to constant weight at a tempera- 
ture between 100 and 110C. (212 and 230F.), cooled, 
and weighed to the nearest 0.5 g. Record this weight 
as weight A. In the case of homogeneous material, the 
smallest particles in the sample may be retained on a 
screen having lj^-in. circular openings. 

2. Immerse the sample in water for 24 hours, surface- 
dry individual pieces with aid of a towel or blotting 
paper, and weigh. Record this weight as weight B. 

3. Place the sample in a wire basket of approximately 
j/4-in. mesh, and about 12.7 cm. (5 in.) square and 10.3 
cm. (4 in.) deep, suspend in water 1 from center of scale 
pan, and weigh. Record the difference between this 
weight and the weight of the empty basket suspended in 

1 The basket may be conveniently suspended by means of a fine 
wire hung from a hook shaped in the form of a question mark with 
the top resting on the center of the scale pan. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 105 

water as weight C. (Weight of saturated sample im- 
mersed in water.) 

4. The apparent specific gravity shall be calculated by 
dividing the weight of the dry sample (A) by the differ- 
ence between the weights of the saturated sample in ai r 
(B) and in water (C), as follows: 

A 

Apparent Specific Gravity = p _ /v 

5. Attention is called to the distinction between appar- 
ent specific gravity and true specific gravity. Apparent 
specific gravity includes the voids in the specimen and is 
therefore always less than or equal to, but never greater 
than the true specific gravity of the material. 

APPROXIMATE METHOD. Weigh graduate and fill half 
full of water and weigh again, being careful to see that 
weight of water and volume check. Add an equal volume 
of the dry aggregate after weighing, and note the exact rise 
of the water level. Let W = weight of material, and G 
weight of water displaced. Then specific gravity of the 

W 

material = S = -~- if metric units are employed. 

Report should be in standard form. 

Experiment E-5 

DETERMINATION OF VOIDS IN AGGREGATES 

References. Johnson's Materials of Construction, 
5th Ed. p. 409, 417. 

Taylor & Thompson, 5th Ed. p. 181. 

Hool & Johnson, pages 25, 26, 27. 

The voids in an aggregate are the interstices between 
the particles. 

The total volume of hollow spaces constitute the abso- 
lute voids. The total volume of hollow spaces minus 



106 LABORATORY MANUAL OF TESTING MATERIALS 

volume occupied by moisture constitute the air filled 
voids. 

Material. Any aggregate, usually sand, gravel or 
broken stone, thoroughly dried. 

Special Apparatus. For coarse materials: Use a 
vessel which is water tight and capacity is at least 
J^ cu. ft. Volume of water may be determined by 
weighing. 

Fbr finer materials: Use a 1000 c.c. graduate or 500 c.c. 
graduate if very fine materials are being measured. Vol- 
ume of water may be either measured or weighed. 

Procedure. (a) Determination of Voids by Direct 
Measurements.- In this method determine a known 
volume (varies with size, being larger for coarser sizes) 
of aggregate in the state in which the percentage of voids 
is required, i.e., loose, shaken or packed. 

The method of determining the volume of hollow 
spaces varies with the character and size of particles. 

COARSE AGGREGATE (contains no particles under Y 
in.) . Pour water directly into the aggregate till the voids 
are filled, the volume of the water poured in equals the 
volume of the voids. 

AGGREGATE CONTAINING PARTICLES UNDER M-IN. 
DIAMETER. Either introduce the water slowly from the 
bottom by means of a special apparatus, thus keeping out 
entrained air or pour a known volume of aggregate slowly 
into a known volume of water, noting the rise in level of 
water. The last two methods are not exact inasmuch as 
they allow some entrained air, but they will be found 
sufficiently accurate for practical purposes. 

(6) Determination of Voids by Specific Gravity Method. 
In this method the apparent specific gravity must be 
known or be determined as in Experiment E-4. 

Knowing the specific gravity of the aggregate, the 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 107 

weight of a cubic foot of the solid material may be 
determined. 

Then determine the weight of a known volume of the 
aggregate usually in pounds per cubic foot as determined 
in Experiment E-3) in the state in which the percentage of 
voids is required, that is, loose, shaken or packed. From 
these weights the percentage of voids may be figured. 

Experiment E-6 

EFFECT OF MOISTURE IN AGGREGATES ON PER CENT. OF 

VOIDS 

Object. The object of this test is to determine the 
effect of moisture on concrete aggregates with respect to 
the per cent, of voids. 

References. Taylor and Thompson, pages 137-140. 

Proc. Am. Soc. T. M. Vol. 20. 

Hool and Johnson, page 26. 

Material. The following materials will be used: 
Fine sand, coarse sand, gravel. 

Apparatus. 1000 c.c. graduate, 100 c.c. graduate, 
metric scale, pan. 

Method. Weigh a large 1000 c.c. graduate flask and 
fill half full of the dry material to be tested). Record the 
weight and the level of the material. Pour dry material 
into a pan and add 2 per cent, (by weight) of water to 
dry sand, and agitate thoroughly. Return dampened 
material to flask. Shake well and uniformly (one batch 
no more than the others) and record the new level of the 
sand. Add water in like increments of 2 per cent, until 
the material is thoroughly saturated, recording the new 
level after each addition of water. This determination 
may be made using the apparatus and methods as in 
E-3. Note how sand feels to the touch at different 
per cents, of moisture. 



108 



LABORATORY MANUAL OF TESTING MATERIALS 



Curves. Show by curves the relation between per 
cent, moisture and weight per cubic foot. Show also 
the relation between per cent, voids and per cent, 
moisture. 

Calculations. Assume specific gravity equal to 
2.65, calculate per cent, absolute voids, per cent, 
air voids, weight per cubic foot for each per cent, of 
moisture. 

Report should be in regular form. 



Experiment No. E-7 

STUDY OF SIEVES 

The results of sieving tests will not be comparable and 
specifications cannot be applied properly unless the 
standard sieves present the same spacing and diameter 
of wires. The commercial numbers designating the 
sieves are approximately the number of meshes per 
linear inch. There are three standard series in use at 
the present time. 

I. Tyler Series EACH OPENING DOUBLE THE NEXT LOWER 



No. or size 


Size of clear opening, in. 


Diameter of wire, in. 


200 


0.0029 


0.0021 


100 


0.0058 


0.0042 


48 


0.011G 0.0092 


28 


0.0232 0.0125 


14 


0.0460 0.0250 


8 


0.0930 


0.0320 


4 


0.1850 0.0650 


% 


0.3700 0.0920 


H 


0.7500 


0.1350 


i; 


1 . 5000 





INSTRUCTIONS FOR PERFORMING EXPERIMENTS 109 

II. The A. S. T. M. Standards SEE A. S. T. M. 1916 D-7-16 



No. or size j Size of clear opening, in. 


Diameter of wire, in. 


100 


. 0055 


0.0046 


80 


0.0067 


0.0059 


50 


0.0114 


0.0083 


40 


0.0142 


0.0102 


30 


0.0197 


0.0130 


20 


. 0335 


0.0153 


10 


0.0790 


0.0220 



In sieving observe the following directions: 

Aggregate should be dry. 

Use 100, 250, 500, or 1000 grams of the sample since 
the results are then more easily turned into per cents. 

The samples to be tested and placed on the coarsest 
sieve, which is the top one in the nest. The sieving is 
complete when not more than 1 per cent, passes after 
one minute shaking. 

The results are plotted in a curve showing the per 
cents, retained in the various sieves. The most con- 
venient diagram is on the logarithmic scale. 

Sieve Analysis of Aggregates. A well graded aggre- 
gate contains particles of different sizes. Specifications 
prescribe the amounts of the various sizes of aggregates 
entering into a desired concrete. 

Experiment E-8 
SIEVE ANALYSIS OF AGGREGATES 

The experiment gives graphically the gradations of 
sizes in an aggregate and by comparisons with a 
theoretical ideal aggregate the improvement of the 
aggregate may be known. 



110 LABORATORY MANUAL OF TESTING MATERIALS 

Reference. Trans. American Society Civil Eng'rs, 
Vol. LIX, p. 90. 

Proc. Amer. Concrete Institute, 1917 pages 432 and 
440. 

Concrete Eng'rs Handbook, Hool and Johnson, 
page 23. 

Engineering Record, Jan. 8, 1916. 

Material. Gravel and sand or broken stone with 
screenings, or stone and sand, well dried. 

Apparatus. Any standard sieves or screens may be 
used. The clear opening in inches must be known. 
The Amer. Soc. for testing materials prescribes circular 
openings for sizes y in. and larger. 

Procedure. A representative sample of the aggre- 
gate should be chosen weighing 1000 or 2000 gram. 
The coarser the aggregate, the larger should be the size 
of the original sample. The sample should be separated 
into its sizes by sieving, beginning with the largest 
sieves. The amount remaining on each sieve after five 
minutes, shaking should be weighed, also the amount 
passing the finest sieve. If the sum of these is not 
equal to the original weight, distribute the error 
proportionately. 

Note the actual size of the largest particle in the sample. 

Computations/ Plot a diagram with per cents, pass- 
ing the sieve as ordinates and size of mesh of the differ- 
ent sieves as abscissae. 

Plot also on this diagram, curves representing the 
specifications in Appendix II; and also a curve de- 
scribed as follows : The curve starts upon and is tangent 
to the zero alxis of percentages a't 7 per cent., and runs as 
an ellipse to a point on a vertical ordinate whose value 
represents a size about one-tenth of the diameter of the 
largest particle, and thence by a tangent straight line 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 111 

to the 100 per cent, point on the ordinate of largest size 
of particle in the sample. 

NOTE. This latter curve is Fuller's Maximum Density 
Curve and contains also the cement in an assumed 
proportion. 

The equation for the ellipse is : 

(y - 7) 2 = ~(2a* - * 2 ) 

b a 

For stone and screenings 29.4-j-2.2Z) 0.055+0.147) 
For gravel and sand 26.4+1.3D 0.04 +0.1 6D 

For stone and sand 28.5-fl.3D 0.04 +0.16D 

NOTE. The above constants vary with the different 
materials which may be used in concrete constructions, 
and to be strictly accurate must be determined for each 
material. However, these values may be considered 
average and used as such may be considered accurate 
enough for practical purposes. 

Discussion of Results. In what sizes of particles is 
the aggregate deficient? How may this be remedied in 
a practical way? 

If the aggregate should be screened into two or more 
parts and these recombined in new proportions, indicate 
on what sieves to screen, and' the new proportions of each 
size to use. 

Give the proportions for an assumed concrete. 

INFORMATION 
YIELD OF CONCRETE AND QUANTITIES REQUIRED 

The volume of mixed concrete is approximately two- 
thirds of the total volume of the separate cement, sand 
and coarse aggregate. The volumetric shrinkage of 



112 LABORATORY MANUAL OF TESTING MATERIALS 

sand and gravel when mixed together is about 15 per 
cent. These are rough approximates. The actual 
shrinkage will depend upon the character and sizing 
of the aggregate, consistency, richness of mix, etc. 

Fuller's Rule. Fuller's rule is a simple rule advanced 
by W. B. Fuller as follows: 

Barrels of cement per cubic yard of concrete = 
10.5 



C+S+G 
Number of cubic yards of sand = r . eyTTT X S 



Number of cubic yards of coarse aggregate 
L55 XG 



C+S+G 

Where C = number of parts of Cement. 
S = number of parts of Sand. 
G = number of parts of Coarse Aggregate. 
Thus for a 1 :2 :4 mix 

Bbls. of Cement = -= -7^7-7 = ^=1.50 

i -f" -\ t 

Cubic Yards of Sand = -y- X 2 = 0.45 

This rifle is approximate. The sizing of the different 
aggregates is not considered. 

Approximate amounts of Materials required for 1 cu. 
yd. of concrete. 



Proportion 


Cement, 
bbl. 


Sand, 
cu. yd. 


1 Gravel or stone, 
cu. yd. 


1:2:4 


1.50 0.45 


0.89 


1:2.^:5 


1 . 24 . 46 


0.92 


1:3:6 


1.05 


0.47 


0.93 


1:4:8 


0.81 0.48 


0.96 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 



113 



On account of settlement of stone in transit, from 8 
to 12 per cent., it is usual to order it by the ton. Weight 
of broken stone at the crusher is : for limestone, 2300 - 
2600 Ib. per yd; for trap 2400 - 2700 Ib. per yd. 

Extensive tables will be found in " Concrete, Plain 
and Reinforced" by Taylor and Thompson, pages 213 
to 217. 

Caution. The Aberthaw Construction Company re- 
marks that on account of waste on the job, the direct 
use of these tables will result in a shortage of material. 
The Company estimates the same amount of sand and 
coarse aggregate for 1:2:4 concrete as for 1:1:2, 
varying only the cement. Thus for 1 yd. of concrete. 



Proportion 


Cement, 
bbl. 


Sand, 
cu. yd. 


Stone, 
tons 


1:2> 2 :5 


1.36 


0.50 


1.30 


1:2:4 


1.66 


0.50 


1.30 


1:13^:3 


2.00 


0.50 


1.30 


1:1:2 


2.86 


0.50 


1.30 



1.3 tons of broken limestone is approximately 1 yd. 

Experiment E-9 
HAND MIXING OF CONCRETE 

Hand-mixed concrete is not under so good a control as 
machine-mixed concrete and, therefore, not so uniform. 
The student should learn the appearance and behavior of 
well mixed concrete with respect to consistency, uniform- 
ity, harshness, etc. 

The following directions from the Manual of the Ameri- 
can Railway Engineering Association should be carried 
out. First, however, determine in advance the amount 



114 LABORATORY MANUAL OF TESTING MATERIALS 

of material needed and the proper consistency. (See 
Exper. No. E-ll, E-16, E-17 or F-2). 

" When it is necessary to mix by hand, the mixing shall be on 
a watertight platform of sufficient size to accommodate men 
and materials for the progressive and rapid mixing of at least 
two batches of concrete at the same time. Batches shall riot 
exceed J^ cu. yd. each. The mixing shall be done as 
follows: the fine aggregates shall be spread evenly upon the 
platform, then the cement upon the fine aggregates, and these 
mixed thoroughly until of an even color. The water necessary 
to mix a thin mortar shall then be added and the mortar spread 
again. The coarse aggregates, which, if dry, shall first be 
thoroughly wetted, shall then be added to the mortar. The 
mass shall then be turned with shovels or hoes until thoroughly 
mixed and all the aggregates covered with mortar. Or, at the 
option of the Engineer, the coarse aggregates may be added 
before, instead of after, adding the water." 

Notice that a concrete that appears dry at first will 
become easily flowing after longer mixing. If the 
concrete works harsh and the aggregate tends to sepa- 
rate, more cement or more fine sand is needed. 

NOTE. (1) Does free water appears when the mass is 
struck with a shovel. (2) At what angle with the 
horizontal will the concrete flow off the shovel. (3) 
If the concrete will hold a level surface in a wheelbarrow 
while the aggregate does not sink below the surface. 
(4) If the concrete quakes while it is being tamped to 
position. 

See that the tools are cleaned after use. 

A convenient method for mixing concrete by one man 
is as follows: 

The materials are mixed dry in a mortar box with high 
sides and a sloping end. With the hoe draw the dry 
materials toward the sloping end and supply water as 



INSTRUCTIONS FOR PERFOHM1NG EXPERIMENTS 115 

needed, mixing a small batch of concrete thoroughly. 
When the batch has been used, another small batch is 
mixed in the same manner. 

Experiment E-10 
MIXING CONCRETE BY MACHINE MIXER 

References.- Johnson's Materials of Construction, 
5th Ed. pp. 439-441. 

American Concrete Institute Proceedings. 

Final Report of Joint Committee, Proc. A.S.T.M., 
1917, p. 219. 

Obtain catalogue of type of mixer under operation and 
study design and operation of the machine. Check the 
following: Type: batch; continuous; Discharge: tilting, 
spout. Loading: state method. Shape of Drum, Arrange- 
ment of Interior Blades. Control. Speed of Drum Recom- 
mended. Movement of Concrete in Mixer. Measurement 
of Water. Time. Condition of Blades. Cleanness of 
Interior. 

Observe action of mixer and report following: 

Time Required to Discharge. Does Mixer Scatter Con- 
crete in Discharging? Proportion of Drum Capacity 
filled with Concrete, Time of Mixing. Water, Gallon per 
Bag of Cement. Uniformity of Mixing. What is the 
remedy when the mix separates or works too harsh. 
Output of mixer in cubic yards per hour. 

In mixing with batch machines, it is desirable to 
admit the sand, cement and stone in the order named 
a'nd mix dry for at least 10 or 15 seconds. The water 
should then be rapidly added and the mixing continued 
for at least one and one half minutes. For machines 
of two or more cubic yards capacity the minimum time 
of mixing should be two minutes. The speed of rotation 



116 



LABORATORY MANUAL OF TKSTING MATERIALS 



should be approx. 16 r.p.m. A speed at the periphery 
of the drum of about 200 ft. per minute is a general 
average for different types of mixers. 

Experiment E-ll 
AMOUNT OF WATER REQUIRED FOR MIXING 

Cement and water form a paste that binds the aggre- 
gate together and lubricates the aggregate to permit 
thorough mixing. An excess of water unduly dilutes 
and weakens the cement paste. Therefore, the minimum 
amount of water should be used that will give the re- 
quired work ability, mobility, or consistency to the con- 
crete. This consistency is kept constant on any one job 
but varies with the job. A thin wall with steel rein- 
forcements requires a wet concrete; concrete road, a 
medium concrete; sidewalk base, a dry concrete. 

The richer the mix, the more water required (22 per 
cent, by weight) to hydrate the cement. The amount of 
water in concrete is best expressed as the volume of 
water relation to the volume of cement. A volume, 

RULES FOR USUAL CASES OF USUAL AGGREGATES 



Kind of work 


Mix 


Gallons of 
water per 
bag of 
cement 


Slump 
test, 
in. 


Relative 
con- 
sistency 


1-2-3 tamped concrete 
123 concrete road 


Work 

Work 


S^'-G 


5-G 


.0 
10 


1-2-3 reinforced concrete . . . 


Work 




8-10 


.25 


1-2-4 tamped concrete 
1-2-4 concrete road 


.Work 

Work 


6 -G.H 


5-6 


.0 
.10 


1-2-4 reinforced concrete . . . 


Work 


73^-8 


8-10 


.25 



ratio of 0.8, is 0.8 cu. ft. of water to 1 cu. ft. of packed 
cement, i.e., nearly 6.4 gal. per bag of cement. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 117 

The water absorbed in a porous aggregate, and the 
moisture in an aggregate that has been exposed to the 
weather, must be added to or subtracted from the above 
table. 

The finer the aggregate the more water is required to 
wet the surface of the particles. For instance, fine sand 
requires more water than coarse sand and, therefore, the 
cement must be increased if the same strength of paste 
is expected. 

METHODS OF MEASURING CONSISTENCY 

Such methods are not well standardized. 

Experiment/ Determine the amount of water re- 
quired to bring about a consistency, described below, 
of a 1-2-3 mix, using a local aggregate from the field. 

Consistency. The consistency of the concrete shall be 
such that when a cylinder 6 in. in diameter and 12 in. in 
length is filled with concrete and tamped until all voids 
are filled and a slight film of mortar appears on the sur- 
face and the cylinder then removed, the vertical settle- 
ment or "slump" of the concrete shall not exceed 2 in. 
when a mechanical finishing machine is used, nor more 
than 4 in. when the finishing is done by other methods 
permitted in these specifications. 

Consistency is usually judged by the general behavior 
of the concrete but sometimes tests are specified. 

Description of Slump Tests/ (a) By the Slump Test 
development of Abrams, which is thus performed. 

Mix the concrete thoroughly, adding the estimated 
amount of water. 

Tamp the concrete into a galvanized iron mold which 
is a cylinder 6 in. in diameter and 12 in. high. The 
cylinder is filled in two layers. Each layer is tamped for 
40 strokes with a % in. round steel rod. 



118 LABORATORY MANUAL OF TESTING MATERIALS 

Then draw the mold up, off the specimen, and note 
how much the specimen shortens or slumps in height. 
The consistency is expressed by the slump. Consist- 
ency = 1.0, slump is % to 1 in. Consistency = 1.10, 
slump is 5 to 6 in. Consistency = 1.25, slump is 8 to 
10 in. 

This test applies to sands and gravels rather than to 
sand and broken stone. It is more reliable for wet mixes. 

(b) The Roman Cone Test for Consistency. In place of 
the cylinder a truncated cone is used, 8 in. diameter of 
base, 4 in. diameter of top and 12 in. high. The concrete 
shall be lightly tamped with a rod as it is placed in the 
mold, which when filled is to be immediately removed by 
means of handles on either side of the mold and the 
slump or settlement of the concrete noted. For concrete 
to be finished by a mechanical tamping machine the 
slump shall not be less than % in. nor to exceed 1 in. 
If the concrete is to be finished by hand methods the 
slump may be as much as \ l /2 in. Experience in deter- 
mining the consistency of concrete with the truncated 
cone apparatus would indicate the following " slumps:" 
Very dry consistency, no "slump;" fairly dry consistency, 
% to 1 in.; medium to wet consistencies, 1 to 4 in.; wet to 
sloppy consistencies, 4 to 8 in.; very sloppy consisten- 
cies, above 8 in. 

(c) Bureau of Standards: Jigging or Flow Table Test. 
The Jigging Test developed by the Bureau of Standards 
employs a table top raised vertically to a fixed height by 
means of a cam working at the end of a vertical shaft. 
A mass of concrete is molded in the center of the table in 
a sheet metal mold which has the shape of a hollow frus- 
tum of a cone. For aggregates up to 2 in. maximum size 
this cone has a height of 6 in., upper diameter of 8 in. and 
lower diameter of 12 in. For smaller aggregates a mold 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 119 

having a height of 3 in., upper and lower diameter of 4 in. 
and 6 in. respectively may be used. After molding with 
as little tamping as is needed to fill the form, it is with- 
drawn and the table top is raised and dropped 15 times 
through J<2 inch after which the new diameter of the mass 
is measured. Usually the mass flattens and spreads con- 
centrically. Two diameters at right angles, the long 
and the short if difference is apparent, are measured by 
means of a proportional caliper which is so graduated 
that the sum of the two readings gives directly the 
" relative flowability," which may be expressed as the 
new diameter, divided by the old, multiplied by 100. 

Using a mass of the size and shape described above we 
find that a flowability of 180 is probably as stiff a con- 
crete as can be chuted and placed for reinforced concrete 
work in practice. A flowability of 240 is probably as 
great as is ever needed or should ever be permitted since 
the addition of more mixing water may result in excessive 
segregation. 

ARTICLE 6 
PROPORTIONING MORTARS AND CONCRETES 

Information -12 
Theory of Proportioning Concrete 

A critical study of methods of proportioning concrete is 
at present (1920) under way. The problem may be thus 
stated: 

For construction: 

Given Conditions. 1. The strength. 2. The consist- 
ency. 3. The exp'ected aggregate, (which may vary 
in sizing of particles). 



120 LABORATORY MANUAL OF TESTING MATERIALS 

Factors to be Adjusted.-!. The amount of cement. 
2. The amount of water. 3. The relative proportions 
of fine and coarse aggregate. 

1. The usual practice is to specify the arbitrary mix 
of 1-1^-3, 1-2-3, 1-2-4, 1-3-6, thus decreasing the 
proportion of cement as a weaker concrete is desired. 
The sizes of the aggregates are specified in advance. 

2. Formerly a rough idea of the mix was obtained 
from the measured voids in the aggregate. Void 
determinations are subject to so many errors that this 
method is not used. 

3. The method of volumetric synthesis uses trialmixtures. 
That mix is selected which will produce the densest 
concrete, i.e., one which will yield the least volume in 
relation to the quantities entering into the mix. 

4. Proportioning by adjusting the relative amounts 
of the particles of different sizes to follow the distribu- 
tion indicated by an ideal curve, as for instance an 
ellipse. See Experiment No. E-14. 

5. Proportioning gravel concrete by increasing the 
cement when the per cent, of sand in the aggregate 
increases. Deposits of gravel necessarily vary in rela- 
tive amounts of sand and pebbles. Usually there is an 
excess of sand which may all be used, if a richer mix is 
specified. Crum's Method (see Am. Soc. T.M.) gives 
the amount of cement to produce a concrete of standard 
quality. The amount of sand and its weight must be 
measured. (See Table Rec. by Crum, Amer. Soc. for 
Test Mat. 1919, pp. 462.) 

6. Proportioning by Surface Area, Edwards and Young, 
(see Proc. 1918 A.S.T.M.) indicate that the surface area 
of the aggregate is the most important determining factor 
in the proportioning. The cement paste must cover the 
surface of the particles. The surface area is actually 



INSTRUCTIONS FOE PERFORMING EXPERIMENTS 121 

calculated, for example 700 sq. ft. per 100 Ib. of aggregate. 
An amount of cement is supplied to fit the job, thus for 
a first class concrete 2J Ib. of cement for each 100 sq. 
ft. of surface, or in this case, 7J^ Ib. cement for 100 Ib. 
of aggregate, or roughly 0.186 of cement per 100 Ib. of 
aggregate, or roughly 1 :4.6. For details of this process 
see Experiment No. 16. 

7. Proportioning by Fineness Modulus Abrams (Bul- 
letin No. 1. Structural Materials Research Laboratory, 
Lewis Institute, Chicago) discovers that a certain grada- 
tion of aggregate accompanies the maximum strength. 
The gradation is expressed by the Fineness Modulus. 
The Fineness Modulus is calculated thus 
Sieve a sample of the aggregate through the following 
set of Tyler sieves: \Y 2 , %, %, Nos. 4, 8, 14, 28, 48, 
100. Add the percentages retained on the sieves and 
divide by 100. The Fineness Modulus is an expression 
of the area under a curve representing the sieve test. 
Evidently a number of curves, sizings of fine and coarse 
aggregate rather than one ideal curve, will produce a 
given Fineness Modulus, and therefore a given strength. 
If the Fineness Modulus and water-ratio are kept con- 
stant, a constant strength will result. But if the con- 
sistency is changed by the addition of water, the cement 
must be increased to preserve constant the water-ratio. 
See Experiment on Fineness Modulus, E-17. 

Experiment E-13 
MIXTURE- OF FINE AND COARSE MATERIAL 

Purpose.- The purpose of this experiment is to de- 
termine the increase in volume in an aggregate caused by 
the addition of a given volume of a finer material. 

References. Tayler & Thompson, Concrete, Plain and 
Reinforced,, 1907, Chapter VI, p. 10. 



122 LABORATORY MANUAL OF TESTING MATERIALS 

Baker's Masonry Construction, 1910, Paragraphs 297 
to 300. 

Special Apparatus. 
For fine materials. 
A 500 c.c. graduate. 
Scales for weighing with gram weights. 
A small wood tamper. 
For coarse materials. 

An iron vessel (an 8-in. pipe 1 ft. long with one 
end closed water tight is a convenient appara- 
tus). 

A steel scale or other means of measuring con- 
tents of vessel. 

\ 

Method of Test. The coarser material should be in 
the condition in which it is being used on the work. A 
given volume of this should be determined by tamping 
into the measuring vessel in small quantities. It should 
then be emptied out upon a non-absorbent surface or 
pan and to it the desired volume of finer material be 
added and the whole thoroughly mixed. The mixed 
materials should then be tamped back into the measuring 
vessel and the increase in volume determined. 

Report. The report should be in the standard form. 

What is the significance of the results of these tests in 
the proportioning of concrete materials? 

Experiment E-14 

PROPORTIONING CONCRETE BY METHOD OF SIEVE 
ANALYSIS 

The cases which may arise are in general, the folio wing: 
CASE 1. A single aggregate is separated into two or 
more sizes and re-combined. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 123 

CASE 2. Two or more aggregates are to be combined. 
(a) When their analysis curves meet, but do not 

overlap. 
(6) When their analysis curves wholly or partly 

overlap. 

Procedure. Case 1. Perform the operation of me- 
chanical sieving upon the aggregate and draw sieve 
analysis curve together with curve for ideal mixture as 
directed in Experiment E-8. 

Study the curves to decide how many and what sizes 
to screen the aggregate into so that the re-combination of 
parts may be as near as practicable to the ideal curve. 

NOTE. It is not. practicable in most cases, on 
account of extra expense, to screen into more then three 
sizes of aggregate. 

Now treat each size of aggregate as a complete sample 
and re-draw its curve to the original scale. This is 
most easily done by manipulation of values by slide 
rule. See Fig. 28a. 

There are now represented on diagram sheet, two or 
more aggregates, as the case may be, whose curves do not 
overlap in sizes, and drawn to the same scale. These 
should be combined according to the demands of the 
ideal curve for the mixture. 

Give the percentages of each to use and draw the 
combined curve. For methods, see Reinforced Concrete 
Construction, Vol. I by Hool, p. 7. or Concrete, 
Plain and Reinforced, p. 190-200 by Taylor and 
Thompson. 

Give the proportions by weight for an assumed con- 
crete, i.e., 1 to x concrete. 

CASE 2. (a) Perform the operations and draw the 
curves as in Experiment E-8. The curves of the dif- 
ferent aggregates should be drawn to the same scale on 



124 



LABORATORY MANUAL OF TESTING MATERIALS 




INSTRUCTIONS FOB PERFORMING EXPERIMENTS 125 

the same sheet. The Ideal curve for the mixture 
should be drawn from the 100 per cent, point on the 
ordinate of the largest size of particle and the coarsest 
aggregate. The method of combining the different 
aggregates is given in Case 1. 

(6) Perform the operations and draw the curves as 
directed in E-8 and (a) above. 

For method of combination and drawing combined 
curves see Concrete, Plain and Reinforced, by Taylor 
and Thompson. 

ILLUSTRATION OF METHOD or PROPORTIONING CON- 
CRETE BY SIEVE ANALYSIS 

In Fig. 28 (a) the following curves are shown: 

Curve A represents the ideal curve of maximum den- 
sity for a mixture of cement, sand and gravel where the 
size of the largest particle is 1J^ in. 

Curve B represents an ordinary "Run of Bank" 
sample of gravel in which the size of the largest particle 
is 1J in. 

Curve C represents a 1 to 5 (by weight) mixture of 
cement and gravel as shown in Curve B. 

Curve D represents the sand finer than Y in. in the 
Run of Bank gravel, plotted to the same scale. 

Curve E represents the gravel coarser than % in. in 
the "Run of Bank" as represented by Curve B and 
plotted to the same scale. 

Curve F represents a 1 to 5 (by weight) mixture of 
cement and sand as represented by Curve D and gravel 
as represented by Curve E. 

Any mixture of cement and the run of bank gravel as 
represented by Curve B, will be far from the ideal maxi- 
mum density mixture as represented by Curve A. If, 
however, the run of bank is screened into two parts, i.e., 



126 LABORATORY MANUAL OF TESTING MATERIALS 

sand finer than J4 m - represented by Curve D and gravel 
coarser than y in. represented by Curve E, the mixture 
of cement plus aggregate may be made to conform closely 
to the ideal. The ratio of cement to aggregate must be 
assumed in any case and depends upon the quality of 
concrete desired . In Fig. 28a the ratio of cement to aggre- 
gate was assumed to be 1 to 5 by weight. In any mixture 
of 1 to 5 concrete the cement is 1 divided by 6 equals 16.6 
per cent, by weight of the whole. The ideal calls for 
37 per cent, finer (equals sand plus cement) than a J 
in. size and 63 per cent, coarser than J4 m - size. To give 
a still closer approach to the ideal 35 per cent, finer than 
J4 in. and 65 per cent, coarser than J in. were taken. 

The mixture, to conform closely to the ideal, will have 
then 35 per cent, by weight finer than Y in. and this 
will be made up of sand plus cement, and since the 
cement in a 1 to 5 mixture is 16.6 per cent, of the whole, 
then 35 16.6 = 18.4 per cent, is the per cent, by weight 
of sand smaller than Y in. in the mixture. The pro- 
portions of cement, sand, and gravel for the total mixture 
of 1 to 5 concrete are then 16.6 per cent, cement, 18.4 per 
cent, sand as represented by Curve D and 65 per cent, 
gravel as represented by Curve E. This corresponds to 
the proportion by weight of 1 : 1.1 : 3.9. The propor- 
tions by volume as used on the work will be determined 
from the unit weights of the materials. The bulking 
effect of moisture should be taken into account in this 
transformation of proportions. See Exp. E-3 and E-6. 
And the curve of the mixture (Curve F) is seen to con- 
form much closer to the ideal maximum density curve 
than a 1 to 5 mixture (Curve C) of cement and the 
original "Bank Run" gravel. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 127 

Experiment E-15 
STRENGTH AND DENSITY 

The object of this test is to determine which of two or 
more sands will give the denser, and the stronger, mortar 
in any given proportion. 

References. Natl. Assoc. of Cement Users, Vol. II, 
p. 24. 

Taylor & Thompson, Concrete, Plain and Reinforced. 

Johnson's Materials of Construction, 5th Ed. p. 411- 
413, 429. 

Hool & Johnson, Handbook, p. 68. 

Materials. Two or more sands or other fine aggre- 
gate to be used in concrete construction. The test should 
be made on a dry sample of the sand, but if sand as used 
in the work contains moisture, correction of the propor- 
tions found, must be made for the amount of moisture 
present. 

Method. The proportions of cement and sand should 
be such by dry weight as to give the desired proportion 
by moist volume, that is the proportions actually to be 
used on the work. This will of course have to be ascer- 
tained in any given case. 

A batch of ... grm. of the dry materials should be well 
mixed for about one minute in a clean shallow pan. An 
amount of clear water should be then added to give a 
plastic mortar and the whole well mixed for 4 minutes. 
The mortar should then be lightly tamped into a 500 c.c. 
graduate or any form of graduated yield apparatus with 
a light wood tamper. About 20 c.c. of the mixture 
should be introduced at a time. After allowing the 
mortar to settle for some time the volume of mortar 
should be read. 



128 LABORATORY MANUAL OF TESTING MATERIALS 

The other sands should be treated in the same way 
using the same proportions by dry weight and enough 
water to give the same consistency. 

The sand which gives the least volume of mortar, i.e., 
which has the least volume of voids is the best sand pro- 
vided there is no other ingredient present to affect the 
strength and setting. 

If desired, strength test specimens may be molded from 
the resulting mortar in each case. The method of 
molding specimens should conform to the best practice 
as given in standard methods of testing cement. See 
Experiments D-6 and D-7. Tests should be made at end 
of 7 or 28 days. 

Report. The report should be in standard form. 



Experiment E-16 
EXPERIMENT ON SURFACE AREA OF AGGREGATES 

References: Proceedings of Amer. Soc. for Testing 
Materials, Vol. 18, page 235 and Vol. 19, page 444. 

The surface area of aggregates is sometimes used as a 
measure of their value for concrete. A coarse sand, for 
example, has less surface area to be covered with cement 
paste, and requires less water for mobility than a fine 
sand of equal volume. 

Method of Determination of Surface Area. 1. 
Sieve a sample of gravel; determine its weight per cubic 
foot. Sieve it through the following Tyler sieves 1^2, 
%, %, No. 4, 8, 14, 28, 48, 100. 

2. Count the number of particles per gram or fraction 
for extreme small sieves per ounce between the smaller 
intermediate sieves, and per pound between the larger 
sieves. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 129 

3. Determine the specific gravity of the aggregate 
and calculate the weight of solid cubic inch. See 
Exp. E-4. 

4. Calculate the number of particles required to form 
this solid volume and therefrom the average volume of 
one particle. 

5. Assuming this volume to be a sphere, calculate its 
diameter and surface area, and total surface area of the 
particles per unit weight. 

6. Express the result in square feet per 100 Ib. of 
aggregate between each sieve and for entire sample. 

The following formula may be conveniently used: 



= 236.1^/1 



where A = Surface Area in square feet per 100 Ibs. 
S = Specific Gravity of material. 
N = Number of grains per gram in any size of 
separation. 

7. Make graph with diameter of particle as abscissa 
and square feet per 100 Ib. as ordinate. If 3 Ib. of 
cement are to be used for every 100 sq. ft. of surface 
of aggregate, how many bags of cement will be used 
to a cubic yard of this mixed aggregate? 

With water ratio of 0.85, how many gallons of water 
per bag of cement? If the proportions are stated in 
terms of mixed aggregate, as 1 : 4.2, how can this be ex- 
pressed in terms of separate volumes of sand and coarse 
aggregate? 

The Hydro-Electric Commission of Ontario propor- 
tions concrete on the basis of surface area. (See Eng- 
ineering News-Record, Vol. 84, page 33.) 



130 LABORATORY MANUAL OF TESTING MATERIALS 

Experiment No. E-17 
EXPERIMENT ON FINENESS MODULUS 

The Fineness Modulus is used as an expression of that 
gradation of sizes of aggregates which will produce good 
concrete. A Fineness Modulus of 5)^ to 6 is favorable. 

With same aggregate as in Experiment No. E-16 on 
Surface Area, determine the Fineness Modulus, i.e., the 
sum of the per cents, retained on the sieves divided by 
100. 

(1) Report Fineness Modulus of sand and pebbles 
separately and combined. 

(2) Report per cent, of sand and pebbles in mixture. 

(3) Check application of following formula. 
Fineness Modulus of mixed aggregate = F. M of 

sand x per cent, of sand + F.M. of pebbles x per cent, 
of pebbles. 

Work following numerical problems. 

(1) The F. M. of sand is 3.05, and of pebbles is 7.50. 
Required per cent, of sand to produce a mixed aggre- 
gate whose F. M. is 6.0. 

(2) When sand and pebbles are mixed the resulting 
volume will be about 0.86 of the total separate volumes, 
(a) a mix of 1^-2): 4 will be a proportion of 1 : 6X0.86 
or 1 : 5.16 combined, (6) a mix of 1 :4.2 combined 
aggregate will be what? When expressed as separate 

4 2 

or loose volumes? -^ = 4.9 loose volumes. 

.ou 

The aggregate sieves to show 40 per cent, sand and 
60 per cent, stone. Therefore 

4.9X40 per cent. =1.96 sand 

4.9X60 per cent. =2.94 sand, or approximately 

1:2:3 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 131 

(3) Concrete for a road construction is specified to 
be mixed 1 : 2 : 3, that is 40 per cent, sand and 60 per 
cent, pebbles. The available sand is finer than the 
specifications allows. What should new proportions be 
for a concrete of equal strength, and the fine sand used? 
Tests on the aggregate show the following;: . 

F. M. fine sand =2.40 Weight Ib. per cu. ft. = 102 
F. M. coarse sand =3.30 Weight Ib. per cu. ft. = 116 
F. M. pebbles =7.25 Weight Ib. per cu. ft. = 112 

Weight of mixed aggregate with coarse sand = 130 
Ib. per cu. ft. 

Calculations. Real Mix =1 : (2+3) 0.86 = 1:4.3. 

F. M. of mixed aggregate (coarse sand) =3.30 X. 40+ 
60X7.25 = 5.67 

The F. M. of the aggregate with fine sand must also 
be 5.67. Per cent, fine sand = 
7 05 _ 5 A 7 



7726=230 

Per cent, of pebbles = TTvT^.S per cent. 



The mix will be as before 1 : 4.3 mixed or 1 : 5 loose 
volumes. 
The proportions will be 

Sand 5 X .325 = 1.62 

Pebbles 5X,67 = 3.38, or 1: 1.62: 3.38. 

We have thus added coarse material by adding more 
pebbles. This mix should be tested to see if it works 
properly on the job. 

Repeat this calculation for the material tested in this 
experiment. 



132 LABORATORY MANUAL OF TESTING MATERIALS 

Article 7 
TESTS OF CONCRETE AND OTHER BRITTLE MATERIALS 

Experiment F-l 

THE VALUE OF A SAND OK OTHER FINE AGGREGATE AS 
SHOWN BY STRENGTH TESTS 

Purpose. This test is to determine the strength of a 
natural sand mortar as compared with strength of a 
standard Ottawa Sand Mortar. 

References. Indiana State Highway Common Speci- 
fication in appendix, page 160. 

Material. Any sand or fine material used as a con- 
crete aggregate. This material should all pass a J^-in. 
sieve. The original moisture in the sand should be pres- 
ent if possible, in which case a correction for weights 
must be determined by drying a separate sample. 

The cement used should be a mixture in equal parts of 
several standard Portland cements. 

Method. In determining the strength, nine test 
specimens of standard Ottawa sand and cement in the 
proportion of 1 part cement by weight to 3 parts Ottawa 
sand, should be made in the regular way. See Experi- 
ment D-6 and D-7. 

The same number of specimens should be made using 
the sand under test. The correction for weight due to 
moisture should be made. This damp sand should first 
be thoroughly mixed with the required amount of cement 
until the whole is a uniform color. Water should then be 
added until the consistency is the same as that of the 
standard sand mortar. Care should be used in this 
determination. 

Test 3 at 72 hours, 3 at 7 days and 3 at 28 days age. 
Report the strength of each and the average of the three. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 

Report. The report should be in standard form. 
The ratio of the strength of the test sand to that of the 
standard sand mortar should be noted. 

If the sand proves to be defective what tests should be 
made to ascertain the cause? 



Experiment F-2 

(See also Exp. F-3) 

COMPRESSIVE STRENGTH OF CONCRETE 

The object of this experiment will be to determine the 
compressive strength of concrete. 

References. Hool & Johnson " Concrete Engineers 
Handbook." 

Baker's Masonry Construction, pp. 194 to 217. 

Material. Use broken stone (or gravel) up to 1% in. 
sand and Portland cement. 

Apparatus. Six cylindrical molds. 

Method of Making Test Specimens. Make three 
cylinders 8 in.XlG in. or 6 in.X!2 in., using one ^of the 
following proportions : 

1 part cement 1^ parts sand 3 parts broken stone. 

1 part cement 2 parts sand 4 parts broken stone. 

1 part cement 3 parts sand 6 parts broken stone. 

1 part cement 4 parts sand 8 parts broken stone. 

In computing amounts necessary use the rule shown on 
p. Ill, or obtained by methods shown in Experiments 
E-16 or E-17. 

For method of mixing, see Experiment E-9 or E-10. 
Tamp concrete in cylinders in layers of 4 in. A % in. 
diameter steel rod is recommended for rodding the con- 



134 LABORATORY MANUAL OF TESTING MATERIALS 

crete into place. Carefully smooth off the top and make 
cylinder stand vertical. Be sure top and bottom bases 
are both perpendicular to axis of cylinder. Test in 7 or 
28 days. For method of test see F-3 and F-4. 



Experiment F-3 
COMPRESSION TEST BRITTLE MATERIALS 

The purposes of this experiment are : To obtain knowl- 
edge of the proper methods of testing materials in com- 
pression; of the crushing strength of such materials; and 
of the characteristic forms of fracture. 

Material. Three concrete cylinders, or three bricks, or 
terra cotta, or any building material in proper form for 
compression test. 

Preliminary. (1) Before testing any specimen care- 
fully measure its height and cross section. 

2. When brick, stone, concrete, or cement specimens 
are to be tested they should be carefully bedded either 
with blotting paper or with plaster of Paris. (See Fig. 
6.) To bed a specimen with plaster of Paris, have the 
testing machine balanced, and the head down so far 
that it will clear the specimen only about 1 in. or 
2. Then mix some plaster of Paris and water to a 
very thick, creamy consistency. Spread a thin layer of 
this on paper placed upon the spherical bearing block of 
the machine and cover it with a piece of tough sized 
paper, upon which the specimen should then be placed. 
The paper is to keep the water of the plaster out of the 
specimen. Upon another similar piece of paper a similar 
pad of the plaster should be spread covered with another 
piece^of paper to form a pad, and the pad then placed 
upon^the specimen. The head of the machine should 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 135 

then be run down rapidly until it presses upon the plas- 
ter sufficiently to cause it to flow, thus insuring a good 
bedding. With the trowels now fill up all the open spaces 
about the edges of the specimen near the faces of the 
machine. The surfaces of the specimen may be shellaced 
and the plaster of Paris applied directly to them. If it 
is riot desired to cap the specimen in the testing machine, 
oiled plate glass may be used to give a smooth plane 
bearing surface on the plaster of Paris. After letting the 
plaster set until hard, the specimen is ready to be com- 
pressed. Have the work inspected by the instructor 
before proceeding. 

Another method of capping specimens is as follows: 
Make a paste of neat cement or rich mortar at or before 
making the concrete and place the paste on the specimen 
after 2 or 3 hours has elapsed. This should then be 
covered by plate glass or other plane surface until the 
paste hardens. 

In the case of all materials see that the ends of 
the specimen admit of a good even bearing in the 
machine. 

The Test. Using the slowest speed available, now 
compress the specimen, meanwhile keeping the scale 
beam floating; and watch carefully the behavior of the 
specimen. 

Computation. Compute the stress in pounds per 
square inch at first crack, and at maximum load. 

Results. Load and crushing strength at first crack 
and at maximum load or failure, Sketch form of 
fracture. 

Comparison of results with standard values. 

See general form of report. 



136 LABORATORY MANUAL OF TESTING MATERIALS 

Experiment F-4 

COMPRESSION OF BRITTLE MATERIALS WITH DEFORMA- 
TION MEASUREMENT 

References. Walker on " Modulus of Elasticity of 
Concrete" Proceedings A.S.T.M Part II, 1919. 

Hool, Reinforced Concrete Vol. I. 

Object. In addition to determining the maximum 
strength in compression, as in other compression tests, 
it is intended in this experiment to find the strength at 
elastic limit, the modulus of elasticity, and the modulus 
of elastic resilience. 

Material. The material should be of a cylindrical 
form if possible. A gage length of at least 8 in. should 
be available. 

Apparatus. Compressometer reading to 0.0001 in. 

Operations in Testing. Proceed as in other compres- 
sion tests except that the load is applied in increments of 
pounds (about one-twentieth of the probable maxi- 
mum load) and the total amount of compression at 
each increment is measured by a compressometer. (Use 
slowest speed of the machine.) 

Computations. Plot points with load in pounds for 
ordinates and compression in inches for abscissae. Draw 
a straight line averging the points preceding the elastic 
limit, if any; and, tangent to this straight line, draw a 
smooth curve averaging the remaining points. Mark 
the points of maximum load and elastic limit, which latter 
is the point of tangency of the straight line and the 
smooth curve. Then draw a line through the origin par- 
allel to the straight line previously drawn through the 
plotted points. (Do not continue this line beyond elastic 
limit.) Mark the point of elastic limit, if any, on cor- 
rected line. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 137 

The modulus of elasticity is calculated from the 

PI 

formula E = ^- where P and X are the load in pounds and 
r A 

compression in inches respectively, for any point on the 
corrected line; F is the square inches of cross-sectional 
area of the specimen, and / is the gage-length in inches. 
Consult above references for various methods of com- 
puting Mod. of Elasticity. 

The moduli of elastic resilience and of rupture-work are 
the work done on each cubic inch of material in deform- 
ing it up to the elastic limit and ultimate strength re- 
spectively. These moduli may be obtained from the 
curve of plotted points by multiplying the area under the 
curve up to the point considered by the scale value of 
each unit area of the coordinate paper or by computation 
from observed data. 

Experiment F-5 
REINFORCED CONCRETE BEAM TEST 

NOTE. This experiment may be made to apply to 
column or slab tests by changing certain details as to 
shape and arrangement of specimen and reinforcement 
and also measurement of deformations. 

This experiment follows compressive strength test. 
The same proportions will prevail. The object of this 
test is to investigate the action of a reinforced concrete 
beam. 

Material. Same as in Experiment F-2 with the ad- 
dition of steel for reinforcement. 

Method of Making and Test. Make concrete as in 
Experiment F-2 only a little wetter. Place two taper- 
ing wooden plugs on bottom of forms under each rein- 
forcing rod and spaced 10 inches center to center in 
middle of length of beam. Wet forms and cover bot- 



138 LABORATORY MANUAL OF TESTING MATERIALS 

toms of mold with about 1 in. of concrete, then place the 
rods in position. Ram and spade the concrete well 
about forms and rods. Level off the top and cover with 
damp cloth. Sprinkle every day for ten days. 

For compression measurements small iron plugs should 
be set flush with top of concrete, directly over the rein- 
forcement and spaced 10 inches center to center in the 
middle of the beam. Drill holes in the reinforcing and 
plugs as directed. 

The test will be under supervision of the instructor. 
Determine the load-deflection curve and stress in steel 
and concrete, if possible, by means of the Berry strain 
gage. 

Report will cover: 1. Description of materials, kind, 
brand, voids, strength of cement, etc. 2. Proportions. 
3. Design of beam. 4. Per cent, of steel 5. Stresses 
in concrete and steel at first crack and maximum by 
formula, and by test. 6. Location of neutral axis. 

Experiment No. F-6 
BOND STRENGTH OF STEEL IN CONCRETE 

Bond strength is the resistance to withdrawal offered 
by the surface of a steel bar embedded in concrete. At 
low loads this resistance arises from the adhesion between 
steel and the film of cement, as in case of a polished bar. 
When this is overcome, the roughness of surface intro- 
duces bearing and shearing resistance, as in case of a de- 
formed bar with shoulders. An ordinary plain bar with 
uneven surface is a partially deformed bar. 

Select 2 round rods 20 in. long and % in. in diameter 
from each of the following : cold drawn steel with smooth 
surface; ordianry plain reinforcing steel; deformed bar. 
Embed these in cylinders. Pull out the bars at age of 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 139 

28 days, observing (1) stretch of bar, and (2) withdrawal 
from concrete at increasing loads. 

Draw curves of slip against bond stress per square inch 
of embedded surface. Report (1) bond stress at first 
slip, (2) maximum bond, (3) stress in bar at maxi- 
mum bond, and (4) number of diameters of length 
of embedment necessary to develop maximum strength 
of bar. 

Did the cylinder split? Did the bar reach its yield 
point? 

Consult references and report how the results would 
have varied with richer concrete and bars of square or 
oblong shape. 

Experiment No. F-7 
TEST OF CONCRETE REINFORCING FABRIC 

Report on sample furnished the following: Weight 
per 100 sq. ft.; ultimate strength of metal; distribution 
of area of cross-section between longitudinal and trans- 
verse directions. 

Consult catalogue of manufacturer and determine uses 
for which this fabric is recommended. 

Report. See standard form p. 7. 

Experiment F-8 

CROSS BENDING AND COMPRESSION TESTS OF BUILDING 

BRICK 

Reference. Tentative Specifications for Building 
Bricks. Proc. A.S.T.M., 1919, I. 

Purpose. The purpose of the tests is to determine 
the quality of various grades of building bricks. 



140 LABORATORY MANUAL OP TESTING MATERIALS 

Materials. Various kinds and grades of building 
brick as assigned. At least five of each kind should be 
available for each test. 

The bricks should be dried to constant weight. 

Procedure. 

Transverse Test. Test flat-wise on a span of 7 in. with 
the load applied at midspan. Use standard apparatus. 
Determine maximum breaking load. 

Compression Test. Test half -brick on edge. 

1" Cut the brick into halves with mason's chisel. 

2. Apply coat of shellac to upper and lower edges and 
allow to dry. 

3. Apply thin coat of plaster of paris mixed with water 
to the consistency of thick cream. 

4. Apply oiled plate glass and allow to harden. 

5. Test in compression using spherical bearing block. 
Determine the maximum breaking load. 

Report. Follow the standard form on p. 7, 
referring to the above reference for computations and 
specifications. 

Additional Reference: Bulletin No. Ill, Bureau of 
Standards. 

Article 8 
TESTS OF ROAD MATERIALS 

Experiment G-l 
RATTLER TEST OF PAVING BRICK 

Purpose. To determine the effects of impact and 
abrasion in a standard rattler test. 

NOTE. Differentiate these effects in comparing differ- 
ent samples of brick. 

References.- Specifications of the American Society 
for Testing Materials, 1918, p. 549. Judson Roads 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 

and Pavements; Tillotson Paving and Paving Materi- 
als; Baker Roads and Pavements; Bryne Highway 
Construction. Specifications of N. B. M. A. 

Extract from standards of A.S.T.M., 1918, p. 555: 
"The number of bricks per test shall be ten for all 
brick of so-called "block size" whose dimensions fall 
between 8 and 9 in. in length, 3 and 3% in. in breadth, 
and 3% and 4}^ in. in thickness." 

NOTE.' Where brick of larger or smaller sizes than the 
dimensions given above for blocks are to be tested, the 
same number of brick per charge should be used, but 
allowance for the difference in size should be made in 
setting the limits for average and maximum rattler 
loss. 

Note any surface evidences of lamination. Select 
brick which are free from chipped corners and other 
defects. 

Apparatus. The standard rattler of the Amer. Soc. 
for Testing Materials shall be used. (See Standards 1918, 
of Amer. Soc. for Testing Materials, p. 551.) The 
abrasive charge shall consist of cast iron spheres of stand- 
ard composition and of two sizes. Ten large spheres 
3.75 in. in diameter when new weighing approx. 7.5 
Ib. each. The smaller spheres shall be 1.875 in. in di- 
ameter when new. The collective weight of the charge 
shall be as nearly 300 Ib. as possible. 

Procedure. Weigh and place the required number of 
bricks in the rattler. See that the shot makes up the re- 
quired weight for each size; if they do not, place an ad- 
ditional small shot in the rattler. Record the reading of 
the counter. Close the rattler and start. Note the 
rate which should be as near 30 r.p.m. as possible. Only 
one start and stop per test is generally acceptable. 

Results. The loss shall be calculated in percentage of 



142 LABORATORY MANUAL OF TESTING MATERIALS 

the initial weight of the brick composing the charge. 
In weighing the rattled brick, any piece weighing less 
than 1 Ib. shall be rejected. 

Report should be in general form. 

Experiment G-2 

ABSORPTION TEST 

Procedure. Place 5 rattled brick in dry kiln 48 
hours and weigh each brick separately to nearest gram. 
Then place in water completely submerged for 48 hours. 
Place strips H X Y beneath the bricks and between 
them so that faces shall not be in contact. When re- 
moved from water, allow the water to drip from the 
surfaces for aboufc 2 minutes, then weigh separately to 
nearest gram. (Note: When rattled brick are not 
available, use half-brick.) 

Absorption. Subtract the weight of the dry bricks 
from the weight of the wet bricks. Find the per cent, of 
gain in weight, which is called the per cent, of absorption. 

See general form of report. 

Experiment G-3 

ABRASION TEST OF ROCK FOR ROAD MATERIALS AND 
BALLAST 

This test is intended to determine the wearing value of 
road materials. 

References. 1918 Standards of American Society for 
Testing Materials, p. 623. 

Bulletin, No. 347, U. S., Dept. of Agriculture. Office 
of Public Roads. 

Materials. Any rock or like material used in road 
construction. At least 30 Ib. of the material should be 
available for a test. 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 143 

Procedure. The material to be tested should be 
broken in pieces as nearly uniform as possible. There 
should be 50 pieces in the charge, the total weight of 
which shall be 5 kg. All test pieces shall be washed and 
thoroughly dried before testing. The charge is then 
placed in the Deval Abrasion machine and given 10,000 
revolutions at the rate of 30 to 33 r.p.m. 

The Deval Abrasion machine consists of one or more 
hollow iron cylinders, closed at one end and furnished 
with a tightly fitting cover at the other. The cylinders 
are 20 cm. in diameter and 34 cm. in depth inside dimen- 
sions. They are mounted on a shaft at an angle of 30 
with the axis of rotation of the shaft. 

At the end of 10,000 revolutions, the charge is removed 
and those particles retained on a Jf g-in. mesh sieve, 
are thoroughly washed and dried again. 

Computations. Compute the loss in per cent. 

Compute the French Coefficient of 
wear. 

The French Coefficient of wear for any material = 

20 X 7j7 = i r = 7 - where W equals the 

per cent, of wear 

loss in weight under Jf g-in. in size per kilogram of rock 
used. 

Experiment G-4 

CEMENTATION TEST OF ROCK OR GRAVEL OR MATERI- 
ALS OP LIKE NATURE 

This test is intended to determine the comparative 
value of dust from different rocks or gravels as a binder 
in the surface of roads. 

Materials. The materials consist of 1500 grm. of 
coarsely crushed rock broken to pass a J^-in. sieve or 1500 
grm. of gravel as it comes from bank. 



144 LABORATORY MANUAL OF TESTING MATERIALS 

Special Apparatus. A Ball Mill for grinding the materi- 
als. Cementation impact machine for testing briquettes. 

Procedure. Place 500 grm. of the rock together with 
90 c.c. of water in the ball mill. The mill is then revolved 
at the rate of 30 revolutions per minute for two and one- 
half hours, the action of the chilled iron balls in the mill 
grinds the sample to a stiff dough. 

Place about 25 grm. of the dough in the cylindrical 
metal die for molding. The die is 25 mm. in diameter. 
By applying a load directly to the plunger of the die, 
run the plunger down to a maximum pressure of 132 kg. 
per square centimeter. This load is applied only for an 
instant and then released. Remove the briquette and 
measure the height, if it is not 25 mm. in height, the req- 
uisite amount of material should be added or subtracted 
to make the next briquette the required height. 

At least 5 briquettes should be made from each sample. 
These are allowed to dry in room air for 20 hours and 
dried in air of approximately 100C., for 4 hours. After 
cooling 20 minutes in a desiccator they should be tested 
in the impact machine. 

The briquette is placed directly on the anvil under 
the plunger. By placing a drop of shellac on the anvil 
under the briquette, it can be made to stay in its position. 
After adjusting the recording paper and needle, the motor 
is started. The mechanism is such that the briquette 
receives the blow of a 1 kg. hammer at the rate of 60 
per minute. The number of blows it takes to break 
the specimen is recorded on the drum. 

The number of blows necessary to destroy the resilience 
of the briquette, so that no action is recorded on the 
drum, is taken as the cementing value of the specimen. 
There should be obtained an average of at least five speci- 
mens to fix the cementing value of the material. 



INSTRUCTIONS FOR PEKFOBMING EXPERIMENTS 145 



Experiment G-5 

HARDNESS TEST OF ROCK ROAD MATERIALS. Dorry 

Test 

This test indicates the comparative hardness of rocks 
as indicated by their ability to withstand an abrasive 
force. 

Special Apparatus. A diamond core drill for cutting 
out test pieces. A Dorry Abrasion Machine for testing 
hardness. 

Materials to be Tested. Any rock in pieces large 
enough so that cylinders 25 mm. in diameter and about 
25 mm. in height may be cut from them. 

Procedure. Cut out specimens from rock by means 
of a diamond core drill. The ends may be squared by the 
diamond saw. At least two and preferably four speci- 
mens should be tested from each material. 

These specimens should be dried to a constant weight 
at 100C. Before placing in the machine they should bo 
weighed. After placing two specimens in the machine 
start the motor and allow to run for 1000 revolutions at 
30 r.p.m. 

Reweigh the specimens and determine the loss. 

The operation is repeated with the specimen 
reversed. 

Calculations. Express the loss as a per cent, of 
the original dry weight. Compute the coefficient of 
hardness, by the formula: 

loss in grams 
20 - -- 



HJ 



146 LABORATORY MANUAL OF TESTING MATERIALS 

Experiment G-6 
STANDARD TOUGHNESS TEST FOR ROAD ROCK 

In this connection, toughness of rock is taken to mean 
the power to resist fracture by impact. 

Special Apparatus. A core drill 1 in. in diameter for 
cutting specimens. 

An impact machine in which the anvil weighs 50 kg., 
the hammer weighs 2 kg., the intervening plunger weighs 
1 kg. The plunger should bear upon the test piece 
with spherical surface of hardened steel having a radius 
of 1 cm. 

Materials. Quarry samples of rock from which test 
specimens are to be prepared shall measure at least 6 in. 
on a side and at least 4 in. in thickness, and when possible 
shall have the plane of structural weakness of the rock 
plainly marked thereon. Samples should be taken from 
freshly quarried material, and only from pieces which 
show no evidences of incipient fracture due to blasting or 
other causes. The samples should preferably be split 
from large pieces by the use of plugs and feathers and 
not by sledging. Commercial stone-block samples from 
which test specimens are to be prepared shall measure at 
least 3 in. on each edge. 

Specimens for test shall be cylinders prepared as 
described in Section 4, 25 mm. in height and from 24 to 
25 mm. in diameter. Three test specimens shall con- 
stitute a test set. The ends of the specimen shall be 
plane surfaces at right angles to the axis of the cylinder. 

One set of specimens shall be drilled perpendicular and 
another parallel to the plane of structural weakness of the 
rock, if such plane is apparent. If a plane of structural 
weakness is not apparent, one set of specimens shall be 



INSTRUCTIONS FOR PERFORMING EXPERIMENTS 147 

drilled at random. Specimens shall be drilled in a man- 
ner which will not subject the material to undue stresses 
and which will insure the specified dimensions. The 
ends of the cylinders may be sawed by means of a band 
or diamond saw, or in any other way which will not 
induce incipient fracture, but shall not be chipped or 
broken off with a hammer. After sawing, the ends 
of the specimens shall be ground plane with water and 
carborundum or emery on a cast-iron lap until the cylin- 
ders are 25 mm. in length. 

Procedure. At least three and preferably four or 
more specimens should be tested for each rock. These 
should be dried in a constant weight before testing. 
The specimen should be adjusted in the machine, so that 
the center of its upper surface is tangent to the spherical 
surface of plunger. The test shall consist of 1 cm. fall 
of the hammer for the first blow and an increased fall 
of 1 cm. for each succeeding blow, till the piece is 
ruptured. 

Calculations. Compute the energy of the final 
blow. The toughness is represented by the number of 
blovvs necessary to break specimen. 



APPENDIX I 

FORMULAS IN MECHANICS OF MATERIALS 
Tension. 

Relative contraction of area at fracture equals 
Original area area at fracture 

original area 
Relative elongation in gage length equals: 

Length after fracture gage length 
gage length 

Tension and Compression. 

Church's Mechanics. Merriman's Strength of Materials. 

P P 

P= F S =a 

F F PI P PI 8 

E < = E < = F X = E = ae = 

1 1 T"- 1 1 iSf 2 

TT T"*V - V K SfV V 

~ 2 1 "2 E l "2^ c ~2E ' V 

Mod. of Res. =\~ Mod. of Res. = \ 

2 & 2 ft 

Torsion (Round solid shafts) 

Pae Me Ppc 

P. = -j- = y- 8 = j~ 

IP IP J 

E - PaL F - Ppl 

Es ~ ~ 



Mod. of Res. = - 

r 

Cross Bending. 

Me Me 

P= "T $ = "T 

o r>7 q r>/ 

p = rr 2 (Center Loading, Rectangular Section) v^- 

1 P/ 3 1 P/ 3 

E = 48 ^U ^ Center Loaflin s) ^ = 48 77 

148 



APPENDIX 



149 



^3 PL 3 4) 3 PI 3 

E = (Third Point Loading) E ? 1296 57 



Mod. of Res. = \ 
2 Hi 

Impact Bending (Rectangular Beams). Approximate formulas. 

GHl 
p *~ 



E = 

ZA-on" 

Road Materials Formulas 

DEVAL ABRASION TEST 

, Original weight final weight 

Loss per cent, (per cent, wear) = - >. . . , =-T"T 

Origmal weight 

20 
French coefficient of wear = 20 X 

w 

Where w is the weight in grams of the detritus under 0.1G cm. 
(}>{ e m -) m si ze P er kilogram of rock used. 

HARDNESS TEST 

Coefficient of hardness = 20 Y% loss in weight after 1000 
revolutions at 28 r.p.m. 

LEGEND FOR ABOVE FORMULA 

Church Merriman 

Width b b 

Height h d 

Gage length or span I I 

Area of cross section F a 

Moment of inertia 7 7 

Polar moment of inertia I p J 

Radius of gyration k r 

Distance from neutral axis to extreme fiber .... e c 

Total load (concentrated) P P 

Unit stress p S 

Unit stress at elastic limit tension T" 

Total elongation in gage length at or before 

elastic limit . . X e 



150 LABORATORY MANUAL OF TESTING MATERIALS 

Church Merriman 

Unit elongation e e 

Twist in gage length (radians) a $ 

External moment in torsion Pa Pp 

Deflection d f 

Mod. of elasticity (ten. and compression) E E 

Mod. of elasticity (shear) E s F 

Resilience (work done on specimen) U K 

IMPACT BENDING: 

Weight of hammer G 

Span length I 

Fiber stress p 

Modulus of elasticity E 

Total height of drop // 

Deflection (total) due to static load G + deflec- 
tion due to blow. . A 



APPENDIX II 



STRENGTH SPECIFICATIONS FOR STEEL AND IRON AMERICAN 
SOCIETY FOR TESTING MATERIALS, STANDARDS, 1918 



Metal 


Tensile strength, Ib. 
per square inch 


Minmum elon- 
gation, per cent 


Con- 
trac- 
tion 
of area 
per 
cent. 


Ultimate 


Yield 
point 


in 8 in. 


in 
2 in. 


Bridges: 
Structural steel 

Rivet steel 


55- 65,000 
46- 56,000 

55- 65,000 
46- 56,000 

58- 68,000 
45- 55,000 

55- 65,000 

52- 62,000 
45- 55,000 

70- 80,000 
85-100,000 

95-110,000 
90-105,000 

55- 65,000 
68,000 

85,000 
100,000 
100,000 

70,000 

105,000 
115,000 
125,000 




1,500,000 


22 
22 

16 
20 

1,60 


40 
25 

25 
35 

0,000 




ultimate 
1,500,000 


Buildings- 


J-2 ultimate 
Yi ultimate 

H ultimate 
>2 ultimate 

Y% ultimate 

3-3 ultimate 
H ultimate 

45,000 
50,000 

55,000 
52,000 


ultimate 
1,400,000 


Rivet steel 


ultimate 
1,400,000 


Ships: 
Structural steel 

Rivet steel 


ultimate 
1,500,000 


ultimate 
1,400,000 


Boiler and rivet steel for loco- 
motives: 
Flange steel 


ultimate 

1,500,000 
ultimate 

1,500,000 


Fire box steel 
Boiler rivet steel 


Structural nickel steel: 
Rivet steel 

Plates, shapes, bars 

Eye bars, rollers, un- 
annealed 


ultimate 
1,500,000 


ultimate 
1,500,000 


ultimate 
1,500,000 


Eye bars, pins, annealed. . . 
Steel splice bars: 
Low-carbon 


ultimate 
20 

25 


Medium carbon 


High-carbon 
Extra-high carbon 
Quenched high carbon 
Axles: 
Cold rolled steel 






Tens 
14 
10 
10 

18 

12 
10 

8 


!. str. 

35 

16 
14 
12 


65,666 

60,000 
(El. Lim.) 




Tires driving: 
Passenger engines 
Freight engines 
Switching engines 
Steel forgings: 
See Serial, A 18-18, Stand- 
ards, 1918. 


::::::::: 



151 



152 



LABORATORY MANUAL OF TESTING MATERIALS 



QUENCHED-AND-TEMPERED CARBON-STEEL AXLES, SHAFTS, AND 
OTHER FORCINGS FOR LOCOMOTIVES AND CARS 

For forgings whose maximum outside diameter or thickness is 
not over 10 in. when solid, and not over 20 in. when bored. 



Size 


Tensile 
strength, 
Ib. per 
sq. in. 


Elastic 
limit, 
Ib. per 
sq. in. 


Elongation in 2 [ Reduction of 
in., per cent. I area, per cent. 


Inverse 
ratio 


Not 
under 


Inverse 
ratio 


Not 
under 


Up to 4 in. outside 
diameter or thickness, 
2-in. max. wall 

Over 4 to 7 in. in outside 
diameter or thickness, 
3^2-in. max. wall 

Over 7 to 10 in. in outside 
diameter or thickness, 
5-in. max. wall 


90,000 
85,000 
85,000 
82,500 


55,000 
50,000 
50,000 
48,000 


2,100,000 


20.5 
20.5 
19.5 
19.0 


4,000,000 


39 
39 
37 
30 


Tens. str. 

2,000,000 
Tens. str. 

1,900,000 


Tens. str. 

3,800,000 
Tens. str. 

3,600,000 


Outside diameter or 
thickness not over 20 
in., 5 to 8-in. wall 


Tens. str. 
1,800,000 


Tens. str. 
3,400,000 


Tens. str. 


Tens. str. 



APPENDIX 



153 



QUENCHED-AND-TEMPERED ALLOY-STEEL AXLES, SHAFTS AND 
OTHER FORCINGS FOR LOCOMOTIVES AND CARS 

For forgings whose maximum outside diameter or thickness is 
not over 10 in. when solid, and not over 20 in. when bored. 



Class Size 


Tensile 
strength, 
Ib. per sq. in. 


Elastic 
limit, 
min., 
Ib. per 
sq. in. 


Elon- Re- 
ga- duc- 
tion tion 
in 2 of 
in., area, 
min., min., 
per per 
cent. cent. 


Up to 2 in. in outside 










diameter or thickness, 










1-in. max. wall 


95,000-115,000 


70,000 


20 50 




Over 2 to 4 in. in outside 






K 


diameter or thickness, 








Alloy 


2-in. max. wall 


90,000-110,000 65,000 


20 50 


steel, 


I Over 4 to 7 in. in outside 






quenched 


diameter or thickness, 






and 


i SH-in. max. wall 


90,000-110,000 65,000 


20 50 


tempered 


Over 7 to 10 in. in out- 










side diameter or thick- 










ness, 5-in. max. wall. . . 


90,000-110,000 


65,000 


20 50 




I Outside diameter or 










thickness not over 20 








in., 5 to 8-in. wall 


85,000-105,000 


60,000 


20 j 50 












| Up to 2 in. in outside 










diameter or thickness, 










1-in. max. wall 


105,000-125,000 


80,000 


20 50 




Over 2 to 4 in. in outside 






| 


L 


diameter or thickness, 








Alloy 


2-in. max. wall 


100,000-120,000 75,000 


20 50 


steel, 


Over 4 to 7 in. in outside 






quenched 


diameter or thickness, 








and 


SH-in- max. wall 


100,000-120,000 


75,000 


20 50 


tempera! 


Over 7 to 10 in. in out- 










side diameter or thick- 










ness, 5-in. max. wall. . . 


100,000-120,000 75,000 


18 45 




Outside diameter or 






thickness not over 20 




in., 5 to 8-in. wall 


9.-),00()-l 1 5,000 70,000 


18 45 



154 



LABORATORY MANUAL OF TESTING MATERIALS 



Metal 


Tensile strength Ib. 
per square inch 


Minimum elon- 
gation per cent. 


Con- 
trac- 
tion 
of area 
per 
cent. 


Ultimate 


Yield 
point 


in 8 in. 


in 
2 in. 


Steel castings: 
Hard castings 


80,000 
70,000 
60,000 

55-70,000 
70-85,000 
80,000 min. 
55-70,000 

70-85,000 

80,000 min. 
Recorded 
only 

80,000 
80,000 

48-52,000 
50-54,000 
48,000 

45,000 

18,000 
21,000 
24,000 
45,000 


1 0.45 r 
t ultimate j 

33,000 
40,000 
50,000 
30,000 

40,000 

50,000 
55,000 

50,000 
50,000 

0. 6 ultimate 
0. 6 ultimate 
25,000 

0.5 ultimate 




15 
18 
22 

22 in. 
4 in. 

7H 


20 
25 
30 

48 
40 

30 


Medium castings 
Soft castings 
Concrete reinforcement bars, 
billet steel: 

Plain, structural grade. . . . 
Plain intermediate grade. . 
Plain, hard grade 
Deformed, structural grade 

Deformed, intermediate 
grade 

Deformed, hard grade 
Cold twisted 


1,400,000 


ultimate 
1,300,000 


Tens. str. 
1,200,000 


Tens. str. 
1,250,000 


Tens. str. 
1,125,000 


Tens. str. 
1,000,000 


Tens. str. 
5 

1,200,000 


Concrete reinforcement bars, 
rail steel: 
Plain bars 


Deformed and hot twisted. 

Wrought iron: 
Staybolt iron 


Tens. str. 
1,000,000 


Tens. str. 

30 
25 
22 

1 


Engine bolt iron 


Refined wrought iron 


Forgings for locomotives 
and cars 

Gray cast iron: 
Light castings 
Medium castings 




Heavy castings 
Malleable cast iron 







NOTE. When not otherwise stated values are the minimum allowed. 



APPENDIX 

METHODS FOR METALLOGRAPHIC TESTS OF METALS 1 
MICROSCOPIC EXAMINATION 

For unhardened iron and steel, the following process has given 
satisfaction: 

1. After polishing, examine under a magnification of 50 to 
150 diameters. Look for slag or cinder in wrought iron, manga- 
nese sulphide, etc., in steel, and size and shape of graphite in 
cast iron. 

2. Etch with a saturated solution of picric acid in alcohol for 
15 seconds. This reveals the pearlite by turning it darker than 
the accompanying ferrite or cementite. In wrought iron, any 
pearlite present shows up, and the general appearance will some- 
times show whether the material was puddled, etc., or made from 
reheated scrap. Those who wish to bring out the ferrite grains 
can do so easily and quickly by etching with nitric acid. To this 
end, nitric acid of 1.42 specific gravity should be diluted with 
either : 

(a) 90 parts by volume of water to 10 of acid, 

(6) 75 parts by volume of water to 25 of acid, or preferably 

(c) 96 parts by volume of amyl alcohol to 4 of acid. 

3. Near the eutectoid point, that is, 0.6 to 1.0 per cent, of carbons 
it is often difficult to distinguish between thin envelopes of ferrite 
and cementite. This difficulty can be overcome by etching with a 
solution of sodium picrate, which turns cementite dark brown or 
black but does not color the other constituents. The solution is 
made by adding 2 parts of picric acid to 98 parts of a solution con- 
taining 25 per cent, of caustic soda, and is used at 100C. 

4. In order to interpret the results of such an etching, they 
should be compared with standard etched specimens. 

5. In the case of hardened and tempered steel the indica- 
tions are less decisive than in the case of unhardened steel, probably 
because the former class has been studied less than the latter. 
Coarse grain, segregation of constituents, presence of oxide, etc., 
are all signs of bad material. For etching use a solution of 4 parts 
of nitric acid, specific gravity 1.42, in 96 of amyl alcohol. The time 
needed has to be found by trial in each case. Hence etch for 5 
seconds, examine, re-etch if necessary, etc. 

6. Macroscopic examination shows up defects due to segregation, 
1 From Standard Methods for Testing. Amer. Soc. for Test- 
ing Materials, 1918. 



156 LABORATORY MANUAL OF TESTING MATERIALS 

blowholes, piping, and the like, and when used in connection with 
microscopic examination yields valuable information. A section 
is cut with a saw, filed smooth, and polished with No. and No. 
00 emery paper; it is then ready for etching. 

Quite a number of etching reagents have been used to develop 
the structure. Whichever solution is chosen, the specimen is 
first carefully washed with a strong caustic potash solution, well 
rinsed under the tap, and then immersed in the etching solution. 
The following may be mentioned : 

(a) Freshly prepared solution of 20 g. of I and 30 g. of Kl, 
in 1000 g. of water. 

(6) Dilute HC1 or H 2 SO 4 up to 30 per cent, acid, using the 1.2 
and 1.84 specific gravity respectively. 

(c) Nitric acid, from 10 to 30 per cent, of the 1.42 specific 

gravity acid in 90 to 70 per cent, of water. 

(d) Concentrated HC1, specific gravity 1.2. 

(e) A solution of 10 or 12 parts of double copper-ammonium 

chloride in 90 or 88 parts of water. 

To bring out the structure of wrought iron rapidly, (d) is 
used, while (c) or (6) will bring it out more slowly. 

For steel, first etch with (a), which shows up the segrega- 
tion of carbon very well. Take care not to over-etch; 5 seconds 
is enough for some materials. To show up the impurities and 
the. segregation of MnS, slag, etc., (d) acts quickly, but (6) gives 
better results though taking longer. 

Some prefer light etching, say after 1 or 2 minutes, but an older 
method is to etch with (6) very deeply, indeed to a depth so great 
that several hours may be needed to reach it. In this way the 
segregation of the carbon and the impurities like slag and MnS 
are shown simultaneously. A picture of the object thus etched 
can be had by treating it like an engraving, that is, inking it with 
printer's ink, and printing on white paper directly from it. A 
common letter-copying press is convenient for this printing. 

STANDARD SPECIFICATIONS FOR PORTLAND CEMENT' 
SERIAL DESIGNATION: C 9-17 

1. Definition. Portland cement is the product obtained by 
finely pulverizing clinker produced by calcining to incipient fusion 
an intimate and properly proportioned mixture of argillaceous and 

Authorized Reprint from the Copyrighted A.S.T.M. Standards 
(1918), American Society for Testing Materials, Philadelphia, Pa. 



APPENDIX 



157 



calcareous materials, with no additions subsequent to calcination 
excepting water and calcined or uncalcined gypsum. 

L CHEMICAL PROPERTIES 

2. Chemical Limits. The following limits shall not be exceeded : 

Loss on ignition, per cent . 4 . 00 

Insoluble residue, per cent . 85 

Sulfuric anhydride (SO 3 ), per cent 2.00 

Magnesia (MgO), per cent 5.00 

//. PHYSICAL PROPERTIES 

3. Specific Gravity. The specific gravity of cement shall be not 
less than 3. 10 (3.07 for white Portland cement) . Should the test of 
cement as received fall below this requirement a second test may 
be made upon an ignited sample. The specific gravity test will 
not be made unless specifically ordered. 

4. Fineness. The residue on a standard No. 200 sieve shall not 
exceed 22 per cent, by weight. 

5. Soundness. A pat of neat cement shall remain firm and 
hard, and show no signs of distortion, cracking, checking, or 
disintegration in the steam test for soundness. 

6. Time of Setting. The cement shall not develop initial set in 
less than 45 minutes when the Vicat needle is used or 60 minutes 
when the Gillmore needle is used. Final set shall be attained 
within 10 hours. 

7. Tensile Strength. The average tensile strength in pounds 
per square inch of not less than three standard mortar briquettes 
(see Section 51) composed of one part cement and three parts 
standard sand, by weight, shall be equal to or higher than the 
following : 

Veeat Tensile 

-Age ell ofrAnirtVi 

test, Storage of briquettes ,, ' ' 

dav4 lb- per 

sq. in. 

7 1 day in moist air, 6 days in water ! 200 

28 j 1 day in moist air, 27 days in water j 300 

8. The average tensile strength of standard mortar at 28 days 
shall be higher than the strength at 7 days. 



158 LABORATORY &ANTJAL OF TESTING MATERIALS 



///. PACKAGES, MARKING AND STORAGE 

9. Packages and Marking. The cement shall be delivered in 
suitable bags or barrels with the brand and name of the manu- 
facturer plainly marked thereon, unless shipped in bulk. A bag 
shall contain 94 Ib. net. A barrel shall contain 376 Ib. net. 

10. Storage. The cement shall be stored in such a manner as to 
permit easy access for proper inspection and identification of each 
shipment, and in a suitable weather-tight building which will 
protect the cement from dampness. 

IV. INSPECTION 

11. Inspection. Every facility shall be provided the purchaser 
for careful sampling and inspection at either the mill or at the site of 
the work, as may be specified by the purchaser. At least 10 
days from the time of sampling shall be allowed for the completion 
of the 7-day test, and at least 31 days shall be allowed for the 
completion of the 28-day test. The cement shall be tested in 
accordance with the methods hereinafter prescribed. The 
8-day test shall be waived only when specifically so ordered. 

V. REJECTION 

12. Rejection. The cement may be rejected if it fails to meet 
any of the requirements of these specifications. 

13. Cement shall not be rejected on account of failure to meet 
the fineness requirement if upon retest after drying at 100C. for 
one hour it meets this requirement. 

14. Cement failing to meet the test for soundness in steam 
may be accepted if it passes a retest using a new sample at any 
time within 28 days thereafter. 

15. Packages varying more than 5 per cent, from the speci- 
fied weight may be rejected; and if the average weight of pack- 
ages in any shipment, as shown by weighing 50 packages taken 
at random, is less than that specified, the entire shipment may 
be rejected. 



APPENDIX 159 

TENTATIVE SPECIFICATIONS ANJQ TESTS FOR COM- 

PRESS1VE STRENGTH OF PORTLAND-CEMENT 

MORTARS 

AMERICAN SOCIETY FOR TESTING MATERIALS 
Serial Designation : C 9-16T 

These specifications and tests are issued under the fixed designa- 
tion C 9; the final number indicates the year of original issue, or 
in the case of revision, the year of last revision. 

ISSUED, 1916 

SPECIFICATIONS 

1. Compressive Strength. The average compressive strength 
in pounds per square inch of not less than three standard mortar 
test pieces (see Section 4) composed of one part cement and three 
parts standard sand, by weight, shall be equal to or higher than 
the following: 







Com- 


Age at 




pressive 


test, 


Storage of tost pieces 


strength, 


days 


, 


Ib. per 






sq. in. 


7 


1 day in moist air, 6 days in water 


1200 


28 


1 day in moist air, 27 days in water 


2000 



2. The average compressive strength of standard mortar at 
28 days shall be higher than the strength at 7 days. 

3. The requirements governing the preparation of standard 
sand mortars for tension test pieces .shall apply to compression 
test pieces. 

SPECIFICATIONS FOR AGGREGATES 

(1) American Railway Engineering Association, 1920, for 
Structures 

Fine Aggregate. The fine aggregate shall consist of sand, 
crushed stone or gravel screenings, graded from fine to coarse, and 
passing when dry, a screen having holes one-quarter (^) inch in 
diameter. Not more than 25 per cent, by weight shall pass a 



160 LABORATORY MANUAL OF TESTING MATERIALS 

No. 50 sieve, and not more than per cent, a No. 100 sieve when 
screened dry, nor more than 10 per cent, dry weight shall pass a 
No. 100 sieve when washed on the sieve with a stream of water. 
It shall be clean and free from soft particles, mica, lumps of clay, 
loam or organic matter. 

Coarse Aggregate. The coarse aggregate shall consist of gravel 
or crushed stone, which, unless otherwise specified or called for on 
the plans, shall, for plain mass concrete, pass a screen having holes 
two and one-quarter (2^) inches in diameter, and for reinforced 
concrete a screen having holes one and one-quarter (1^) inches in 
diameter; and be retained on a screen having holes one-fourth 
(K) m ch diameter, and shall be graded in size from the smallest 
to the largest particles. It shall be clean, hard, durable and free 
from all deleterious matter; coarse aggregate containing dust, soft 
or elongated particles shall not be used. 

(2) Indiana State Highway Commission for Concrete Roads 

Fine Aggregate. The fine aggregate shall consist of sand con- 
forming to the following requirements : 

The sand shall consist of clean, hard, durable grains. When 
dry, it shall pass a laboratory screen having circular openings one- 
quarter ()4) of an inch in diameter. Not more than 50 per cent, 
by weight, shall pass a No. 30 laboratory sieve, and not more than 
10 per cent, by weight, shall pass a No. 100 sieve. It shall be free 
from organic matter and not more than five (5) per cent, by weight, 
shall be removed by the elutriation test. 

Gravel. Gravel shall consist of clean, sound, hard stone, 
reasonably free from soft, thin, or elongated pieces. Gravel 
containing clay or coatings of any character shall not be used. It 
shall show high resistance to abrasion, and no gravel shall be used 
which, in the opinion of the Engineer, does not show wearing 
qualities at least equal to crushed stone having a French coefficient 
of wear of seven (7). Pit run gravel shall not be used. When 
tested by means of laboratory screens having circular openings, 
gravel shall meet the following requirements : 

Passing 2^ inch screen 100 per cent. 

Passing 2 inch screen, not less than 95 per cent. 

Passing % inch screen, 30 to 70 per cent. 

Passing l / inch screen, not more than 5 per cent. 

If the Engineer deems it advisable, he may permit the 
use of material that conforms to all the requirements of the 
specifications for coarse aggregate excepting that of gradation 



APPENDIX 



161 



of sizes, and then provided sufficient additional cement is used 
to produce concrete of a quality equal to that resulting from the 
use of similar aggregate of the specified grading. 

PROPOSED TENTATIVE SPECIFICATIONS FOR COMMERCIAL SIZES OF- 

GRAVEL, BROKEN STONE AND BROKEN SLAG, AMER. Soc. 

FOR TESTING MATERIALS 1920. 

1. These specifications cover the standard size designation 8 
and maximum permissible range in mechanical analyses for nine 
commercial grades of broken stone and broken slag, when used 
in the construction of plain or bituminous macadam, bituminous 
concrete, sheet asphalt and cement-concrete roads and pavements. 

Gravel : 
MAXIMUM PERMISSIBLE RANGE IN MECHANICAL ANALYSES FOR 

EACH SIZE 
Percentage by Weight Passing Each Screen 

Diameter of screen openings, in. 
Designated size, . ___ . 

YA. : '2 a 4 1 I, 1 -J 2 2H I 3H 



- >ia 95-100 

- y^b 85-100 

X- 1 A c 95-100; 

Yi- H c 95-100 

y-\ c 25- 75! 95-100J 

y-\Y-i > ' 25- 75 i 195-100 

H-2 c 25- 75J 95-100 

*-2M c I : 125- 75 95-100 

1 -2 0-15' 85-100; 

2 -3y z \ '' i 0- 15 185-100 

a Additional requirements for grading shall be as follows: 

Passing 20-mesh sieve 25 to 75 per cent. 

Passing 50-mesh sieve not over 25 per cent. 

Passing 100-mesh sieve not over 5 per cent. 

b Limits for silt and clay content may be inserted if desired. 

Any percentage from to 10 per cent, may be designated, with a maximum 
permissible variation therefrom of not more than 2> per cent. 

Broken Stone and Broken Slag. The designated size for each 
grade together with the corresponding maximum permissible 
variations in mechanical analyses as determined by the use of 
laboratory screens, are given in the following table: 
11 



162 



LABORATORY MANUAL OF TESTING MATERIALS 



MAXIMUM PERMISSIBLE RANGE IN MECHANICAL ANALYSIS FOR 
EACH SIZE 

Percentage by Weight Passing Laboratory Screens 



Designated size, 
in. 


Diameter of screen openings, in. 


H 


H 





' 


m 


2H 


m 


- K 

o - y* 
o - x 

Mr X 

x-iy* 

K-VA 
K-VA 
1X-W 

2K-3M a 


85-100 
0- 75 
40- 80 
0- 15 
3- 10 
0- 5 


95-100 
25- 75 


95-100 
95-100 
65- 85 

0- 15 




95-100 
25- 75 
95-100 
0- 15 


95-100 

95-100 
0- 15 


95-100 




25- 75 





















a In the case of light or porous slags a 4-in. maximum size may be specified 
instead of 3> in. 



APPENDIX III 
STANDARD FORMS OF TEST PIECES 



U-About 3^1 a 
!? 



ion not le *s than 9 




_ J_ 

r? T ? ^ 



Etc. 



About 18" 



FIG. 1. Wrought iron, structural steel and boiler plate. Plate 
metal in general. 



k 3 



FIG. 2. Malleable cast iron. 



Radios 
&ot less 
than U" 



214 



H 





! D 


1 



-2 Gage Length-^- 

Kote;-The Gage Length, Parallel Portions and Fillets shall 
be as Shown, but the Ends may be of any Form which, 
will Fit the Holders of the Testing Machine . 

FIG. 3. Structural steel, wrought iron, steel castings and forgings, 
axle and tire steel. 




FIG. 4. Screw end test piece, 
163 



104 



LABORATORY MANUAL OF TESTING MATERIALS 



Kadi as 






not less ["* 
than '4. 


4-U- 


i 

i . _ 






~^ 1 


i r 




r - 


T 1 


? 



U 4-Gage Length- - 

Note '.-The Gage Length, Parallel Portions and Fillets shall be as 
Shown, but h.e Ends ihay b of any Form which will Fit 
the Holders of the Testing Machine . 

FIG. 5. Wrought iron forging for locomotives and cars. 

Mold for Gray Cast Iron Test Specimens. The form and dimen- 
sions of the mold for the arbitration test bar shall be in accordance 
with Fig. 1. The bottom of the bar shall be KG in. smaller in dia- 
meter than the top, to allow for draft and for the strain of pouring. 
The pattern shall not be rapped before withdrawing. The flash 
shall be rammed up with green molding sand, a little damper than 
usual, well mixed and put through a No. 8 sieve, with a mixture 

Pattern 

,*" 

r*i 




U..! 



; i\ Pouring L'asin /'' 

^I^^Js^^i 


Cope 


i 


U 


mj& 


i 


1 




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Borod with 


H 




Hi 




II" 


Teut Holes 


J;V^ 




%PSl 




an 

%$iA 




5 f ^^^^^^^M 





FIG. 6. Mold for arbitration test bar. 

of 1 to 12 bituminous facing. The mold shall be rammed evenly 
and fairly hard, thoroughly dried, and not cast until it is cold. The 
test bar shall not be removed from the mold until cold enough 



APPENDIX 
-Standard Thread' 



165 




FIG. 7. Arbitration test bar. Tensile test piece. 

to be handled. It shall not be rumbled or otherwise treated, 
being simply brushed off before testing. 



APPENDIX IV 



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168 



LABORATORY MANUAL OF TESTING MATERIALS 



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INDEX 



PAGE 

Abrasion test of stone (experiment) 142 

of wood (experiment) 75 

Absorption test of paving brick (experiment) 142 

Accelerated tests of cement (method) 87 

(specification) 157 

Accuracy of testing machines 21, 51 

Aggregates, study of 93 

determination of silt in (experiment) 96 

of voids in (experiment) 105 

effect of moisture on volume of (experiment) 106 

notes on sampling of 93 

sieve analysis of (experiment; 109 

specific gravity of (experiment) 102 

specifications for 159 

weight of 99 

Amsler testing machine 29 

Amer. Soc. Testing Materials; methods for testing cements .. 76 

Amer. Soc. Testing Materials, specifications for cement 156 

strength specifications for steel and iron 151 

methods for metallographic tests of metals 155 

Amount of water required for mixing concrete 115 

Analysis of cement (method) 77 

Apparatus for gripping test pieces in tension 21 

Appendix I, common formulas 148 

IT, strength specifications, iron and steel 151 

specifications, for cement 156 

III, forms of test pieces 163 

IV, strength tables 165 

iron and steel 165 

copper and alloys 166 

timber 167 

stone and brick 168 

171 



172 INDEX- 

PACK 

Applying the load, methods of, in testing machines 27 

Autographic recording apparatus 42 

tension test of iron and steel (experiment) 56 

B 

Bond strength of steel in concrete 138 

Brake beam, flexure test of (experiment) 65 

Brick, strength of (table) 1 68 

cross bending and compression tests of (experiment) .... 139 

Brinell test for hardness 34 

Briquettes, cement 89, 91 

Brittle materials compression tests of (experiment) 134, 136 

C 

Calibration of extensometers 51 

of testing machines 50 

Cast iron, flexure of (experiment) 64 

tension of (experiment) 55 

Cement, Amer. Soc. Testing Materials, methods of testing . . . 76 

Amer. Soc. Testing Materials, specifications for 156 

chemical analysis 77 

compressive strength of (determination) ; 92 

constancy of volume (soundness) 87, 157 

fineness of (method) 83 

(specification) 157 

mixing and molding (method) 84 

mortar, consistency for 86 

specification for 159 

standard sand 89, 90 

tensile strength of 89 

normal consistency neat, Vicat method 85 

sampling, instructions for 76 

specific gravity of (method) 82 

(specifications) , 157 

storage of test pieces 91 

time of setting of, Gil more method 89 

Vicat method 88 

specifications for 157 



INDEX 173 

PAGE 

Cementation test of road materials (experiment) 143 

Columns, test of wood (experiment) 70 

Compression of brittle materials (experiment) 134, 136 

of helical springs (experiment) 62 

short wood blocks parallel to grain 67 

perpendicular to grain 69 

Compressive strength of cement and cement mortars 92 

Compressometers 40 

Concrete, compressive strength of (experiment) 132, 133 

proportioning by sieve analysis 122 

by fineness modulus (experiment) 130 

by surface areas (experiment) 128 

Cone test for consistency 117 

Consistency for cement mortars 86 

Consistency, method of measuring 116 

Constancy of volume of cements 87, 157 

Copper and alloys, mechanical properties of (table) 166 

D 

Definitions 10 

stress 10 

elasticity * 12 

resilience 14 

Density and strength 127 

Drum records from Turner impact machine 31 

E 

Elasticity, definition of 12 

Endurance testing machine 32 

Extensometers, calibration of (experiment) 51 

description of .-. 37 

tension test with (experiment) 57 

F 

s 

Fatigue testing machine 32 

Fineness modulus 130 

Fineness of cements (determination) 83 

(specification) . 157 



174 INDEX 

PAGB 

Flexure tests 25 

test of brake beams (experiment) 65 

of cast iron (experiment) 64 

of large wood beams (experiment) 73 

of small wood beams (experiment) 71 

of reinforced concrete beam (experiment) 137 

Forms of test pieces for iron and steel 163 

Formulas, common 148 

Fractures, materials under compression 17 

under tension 17 

Fuller's maximum density curve 110 

G 

General instructions 4 

Grips, proper arrangement of in tension test 24 

H 

Handmixing of Concrete 113 

Hardness 34 

Brinell ball test 34 

Scleroscope test 34 

test of road materials (experiment) 145 

Helical Spring, compression of 62 

Holding the specimen in tension and compression 21 

in flexure 25 

in shear 26 

Hydraulic testing machines 28 

I 

Identification of woods, laboratory exercise 66 

Impact test of wood beams 74 

Iron and steel, autographic tension test of 56 

fractures of 17 

mechanical properties of (table) 165 

commercial tension test of (experiment) 52 

L 

s 

List of experiments 44 

Load, method of applying, in testing machines 27 



INDEX 175 

PAGE 

Loss on ignition, for cement (determination) 77 

(specification) 157 

M 

Material stressed beyond elastic limit 16 

Metals, methods of metallographic tests of 155 

Method for testing cement, Amer. Soc. Testing Materials ... 76 

Mixing and molding cement test pieces (method) 84 

Mixing concrete by hand 113 

Mixing concrete by machine 114 

Moisture in aggregates, effect of on voids 106 

N 

Normal consistency for cements (determination) ........... 85 

Note keeping 

O 

Organic matter in silt (test) 98 

Ottawa sand 89 

Overstrain, effect of on yield point of steel 63 

P 

Paving brick, absorbtion test (experiment) 142 

rattler test of 140 

Portland cement, definition of ( 156 

specification for 156 

Proportioning concrete by sieve analysis 122 

by fineness modulus (experiment) 130 

by surface areas (experiment) 128 

theory of 119 

Q 

Quartering, sampling aggregates by method of 95 

Quantities required for concrete Ill 

R 

Rattler test of paving brick (experiment) 140 

Reinforced concrete beam, test of (experiment) 137 



176 INDEX 



Reinforcing fabric, test of concrete ....................... 139 

Reports ............................................... 5 

instructions for writing .............................. 7 

Resilience, definition of .................................. 14 

Road materials, cementation test ......................... 143 

hardness test ................... . .................. 1 45 

toughness test ...... ............................... 140 

S 

Sampling aggregates, notes on ........................... 93 

cement, method of ................................. 76 

Sand, strength tests of (experiments) . . . ........... 98, 127, 132 

Sands, yield or volumetric test of (experiment) ............ 127 

Scleroscope, test for hardness with ....................... 34 

Setting of cement, time of (determination) .............. 88, 89 

(specification) ...................................... 157 

Shear tests ............................................ 26 

Shipping and storage of samples of aggregate .............. 95 

Sieve analysis of aggregates (experiment) .................. 109 

proportion concrete by .............................. 122 

Sieves, sizes of commercial (table) ........................ 108 

study of ................................... ........ 107 

Specific gravity of aggregates (experiment) ................ 102 

of cement (determination) ........................... 82 

(specification) .................................... 157 

Specifications for cement, Amer. Soc. for Test. Mat ........ 156 

Standard sand ....................................... 89, 90 

Staybolt iron, vibration test of ........................... 65 

Steel and iron, mechanical properties of ................... 165 

castings, tension test of .............................. 55 

effect of overstrain on yield point of .................. 63 

fracture of ......................................... 17 

tension test of iron and (experiment) ................. 52 

Stone, abrasion test of (experiment) ...................... 142 

strength of (table) ................................. 168 

Storage of cement test pieces ............................ 91 

Strength specifications steel and iron, A. S. T. M .......... 151 

Strength and density ................................... 127 

Stress, definition of ..................................... 10 



INDEX 177 

PAGE 

Study of testing machines (experiment) 48 

Surface areas of aggregates (experiment) 128 

T 

Tensile strength of cements (determination) 89 

(specifications) 159 

Tension test of iron and steel (experiment) 52 

Testing machines 29 

accuracy of 21, 50 

calibration of 50 

endurance 32 

hydraulic 28 

impact 30 

operation of, during test 4 

screw 27 

sensitiveness of 21, 51 

study of (experiment) 48 

table of large, in United States 22 

weighing mechanisms of 35 

Test piece, standard forms of, iron and steel , 163 

pieces, storage of cement 91 

Timber, strength of structural (table) 167 

Torsion, experiment in 59 

Toughness test of road materials (experiment) 146 

Two inch cylinders, unit stresses for (table) 93 



Vibration test of stay bolt iron (experiment) 65 

Voids in aggregates, determination of 105 

Volumetric tests of sands 127 

W 

Weighing mechanisms of testing machines 35 

Wire cable, test of (experiment) 61 

Wood, abrasion test of 75 

beam, flexure of large 73 

of small 71 



178 INDEX 

PAGE 

Wood, beam, impact test of 71 

columns, test of 70 

compression of, parallel to grain 07 

perpendicular to grain 69 

determination of moisture content in 73 

Woods, identification of (experiment) 66 

Y 

Yield or volumetric test of sands 127 

Yield of concrete . . .111 



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STAMPED BELOW 



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THIS BOOK ON THE DATE DUE. THE PENALTY 
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32 



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UNIVERSITY OK CALIFORNIA LIBRARY 






